RIBBON COMMUNICATIONS INC. CONFLICT MINERALS REPORT 2023 PURSUANT TO RULE 13P-1 UNDER THE SECURITIES EXCHANGE ACT OF 1934

Ribbon Communications Inc. Conflict Minerals Report 2023 2 2023 Summary............................................................................................................................................... 3 Introduction .................................................................................................................................................... 4 Company Overview........................................................................................................................................ 4 Conflict Minerals Policy............................................................................................................................................. 5 Products Overview...................................................................................................................................................... 5 Supply Chain and Reasonable Country of Origin Inquiry ..................................................................................... 5 Due Diligence Process ................................................................................................................................................ 5 Due Diligence Measures.......................................................................................................................... 6 OECD Guidance Step 1: Establish Strong Company Management Systems.................................... 6 OECD Guidance Step 2: Identify and Assess Risk in the Supply Chain ............................................ 6 OECD Guidance Step 3: Design and Implement a Strategy to Respond to Identified Risks............... 7 OECD Guidance Step 4: Carry Out Independent Third-Party Audit of Supply Chain Due Diligence .7 OECD Guidance Step 5: Report on Supply Chain Due Diligence ....................................................... 7 Due Diligence Results.............................................................................................................................. 8 Risk Mitigation Steps to Be Taken for 2024 Due Diligence................................................................... 10 Audit............................................................................................................................................................. 10 Important Information Regarding Forward-Looking Statements .......................................................... 11 Annex A List of Smelters.........................................................................................................................................12 Annex B List of Countries ........................................................................................................................................33 RIBBON COMMUNICATIONS INC. (“RIBBON”) presents this Conflict Minerals Report for the reporting period of January 1, 2023 to December 31, 2023 pursuant to Rule 13p-1 under the Securities Exchange Act of 1934 and associated guidance issued by the Securities and Exchange Commission. This document represents Exhibit 1.01 to Form SD, the Conflict Minerals Report.

Ribbon Communications Inc. Conflict Minerals Report 2023 3 852 total suppliers representing100% of in-scope suppliers requested to complete Conflict Minerals Reporting Template (CMRT) 6% more suppliers in scope for CMRT requests compared to 2022 63% of manufacturers were Democratic Republic of the Congo (DRC) Conflict Free 23% of manufacturers were DRC Conflict Undeterminable 79% suppliers completed CMRTs in 2023, an increase of 1% compared to 2022 7% increase in the number of suppliers providing CMRT responses compared to 2022 >44,000 mines used by suppliers completing CMRTs in 2023 14% of manufacturers were not affected 100% of smelters who completed a CMRT maintain a responsible minerals sourcing policy and conduct due diligence with their suppliers 100% of smelters who completed a CMRT filed an independent Form SD

Ribbon Communications Inc. Conflict Minerals Report 2023 4 Introduction This report for the year ended December 31, 2023 has been prepared by Ribbon Communications Inc. (the “Company”, “Ribbon”, “we,” “us,” or “our”) to comply with Rule 13p-1 (the “Rule”) under the Securities Exchange Act of 1934, as amended. The Rule imposes certain disclosure and reporting obligations on companies that report with the SEC and which manufacture, or contract to have manufactured, products containing conflict minerals that are necessary to the functionality or production of those products. Conflict Minerals are defined as cassiterite, columbite-tantalite, gold, wolframite, and their derivatives, which are limited to tin, tantalum, tungsten, and gold (collectively, “Conflict Minerals”). Ribbon has determined that some of the products that it manufactured or contracted to manufacture, and which continue to be manufactured or contracted to manufacture by Ribbon through the end of reporting year 2023 (“Ribbon Products”) include Conflict Minerals. Company Overview Ribbon Communications (Nasdaq: RBBN) delivers communications software, IP and optical networking solutions to service providers, enterprises and critical infrastructure sectors globally. Ribbon helps the world’s leading communications service providers and enterprises embrace the next generation of communications technologies including, cloud-based communications, Internet Protocol, Session Initiation Protocol, Voice over LTE Long Term Evolution, Voice over Internet Protocol, Unified Communications, Web-based Real Time Communications, Edge Computing, Software-Defined WAN, Analytics, Applications Programming Interfaces and Embedded Communications. With more than a thousand customers around the globe and over 20 years of experience transforming and securing networks, Ribbon enables service providers and enterprises to transform their communications networks, quickly deploy new communications networks and services, and capture and retain customers and generate a significant related return on investment. Ribbon’s industry-leading product portfolio ranges from IP Systems, Optical Systems, and session border controllers for service providers and enterprises, intelligent edge with SD-WAN, Network Edge Orchestration, policy and routing, call controllers or soft switches, media gateways, applications platforms, communications clients, and signaling controllers to cloud communications “as a Service” solutions. The Company’s comprehensive portfolio also includes unrivaled end-to-end service assurance, security, fraud management and analytics solutions. All of these solutions are supported by a global services team with extensive experience in design, deployment and maintenance of some of the world’s largest IP and optical networks. The Company is also focused on providing secure carrier-class enterprise communications capabilities to industry verticals including the financial, government, education and healthcare sectors. All of these industries already benefit from Ribbon’s secure, unified, reliable and embedded communications capabilities, which enhance their ability to collaborate and improve productivity. Ribbon maintains a keen focus on our commitments to Environmental, Social and Governance (ESG) matters and report to our stakeholders through our annual Sustainability Report. To learn more about Ribbon, please visit rbbn.com.

Ribbon Communications Inc. Conflict Minerals Report 2023 5 Conflict Minerals Policy Ribbon has adopted a Conflict Minerals Policy and communicated such policy to its suppliers. This policy is available on the Investor Relations-Corporate Governance section of the Company’s website at https://investors. ribboncommunications.com/static-files/79ec23fd-657e-4d9b-8d90-5e2daec9c183. Products Overview This report covers the following Ribbon Products that were manufactured in 2023 (the “2023 Ribbon Products”): SBCs, DSCs, Voice over IP (VoIP) trunking solutions, policy/routing servers, media and signaling gateways, including the GSX 9000 High-Density Media Gateway, IP Optical Solutions, IP Routing Solutions and network analytics tools. Supply Chain and Reasonable Country of Origin Inquiry Ribbon has determined that Conflict Minerals are necessary to the functionality or production of Ribbon Products manufactured or contracted to be manufactured during 2023. We utilize an outsourced supply chain model pursuant to which our contract manufacturers procure materials on our behalf. Our supply chain is multi-tiered, global and complex, and we outsource the manufacturing of our hardware products such that we are many steps removed from the mining and smelting or refining of Conflict Minerals. Therefore, we rely upon our suppliers to provide information on the origin, source and chain of custody of the Conflict Minerals contained in product components and materials. Some of these suppliers may themselves purchase from lower tier suppliers and not directly from a miner, smelter or refiner. The Company conducted a Reasonable Country of Origin Inquiry (“RCOI”) to determine whether any of the Conflict Minerals in our 2023 Ribbon Products originated in the Democratic Republic of the Congo (“DRC”) or an adjoining country (collectively, the “Covered Countries”) and whether the Conflict Minerals are from recycled or scrap sources. Based on our RCOI, we know or have reason to believe that some of the Conflict Minerals in our 2023 Ribbon Products originated in the Covered Countries and are not from recycled or scrap sources. Ribbon’s RCOI measures included conducting a supply-chain survey with in-scope suppliers using the Responsible Minerals Initiative (“RMI”) Reporting Template (the “Template”). The Template was developed to facilitate disclosure and communication of information regarding smelters that provide material to a company’s supply chain. It includes questions regarding the supplier’s conflict-free policy, engagement with its direct suppliers, and a listing of the smelters the company and its suppliers use. In addition, the Template contains questions about the origin of Conflict Minerals included in the company’s products, as well as supplier due diligence. The Template was designed to provide companies with sufficient information regarding their suppliers’ practices with respect to the sourcing of Conflict Minerals to enable such companies to comply with the requirements of the Rule. Due Diligence Process In accordance with the Rule, Ribbon undertook due diligence on the source and chain of custody of the Conflict Minerals in the 2023 Ribbon Products that originated or may have originated in the Covered Countries. The Company’s due diligence measures were designed to conform, in all material respects, to the internationally recognized

Ribbon Communications Inc. Conflict Minerals Report 2023 6 due diligence framework in The Organization for Economic Co-operation and Development (“OECD”) Due Diligence Guidance for Responsible Supply Chains of Minerals from Conflict-Affected and High-Risk Areas (“OECD Guidance”) and the related supplements. Due Diligence Measures Ribbon performed the following due diligence measures in accordance with the OECD Guidance and the Rule: OECD Guidance Step 1: Establish Strong Company Management Systems Ribbon’s Conflict Minerals compliance efforts are overseen by the Company’s Vice President, Manufacturing, Operations and Supply Chain and its manufacturing department, and supported and sponsored by the Company’s engineering, audit and legal departments. Ribbon employees who are responsible for Conflict Minerals compliance have received training regarding Conflict Minerals compliance. The team was structured to ensure critical information, including our policies related to this subject matter, reached relevant employees and suppliers. To the extent red flags or other issues are identified in the supplier data acquisition or engagement processes, these issues and red flags will be addressed first by the responsible individuals within the engineering, audit and legal departments, and, if deemed necessary, will then be reported to and reviewed by the Audit Committee (the “Audit Committee”) of the Board of Directors at regularly schedule meetings on an annual basis. Ribbon also engaged SiliconExpert Technologies, a provider of electronic component data and BOM Management software to the electronics industry (“SiliconExpert”), to assist with its Conflict Minerals compliance efforts. Frequent status meetings are held between Ribbon’s Conflict Minerals support team and SiliconExpert, with Ribbon management receiving status updates on progress and due diligence efforts on a regular and timely basis. In addition, Ribbon has a Conflict Minerals Policy and communicates such policy to its suppliers, which is available on our Investor Relations — Corporate Governance section of our website at https://investors.ribboncommunications. com/static-files/79ec23fd-657e-4d9b-8d90- 5e2daec9c183. To the extent any employee, officer or director has concerns or grievances about the Company’s potential use of Conflict Minerals, such individual is urged to contact his or her manager, the Company’s Chief Financial Officer, the Chief Legal Officer or other member of senior management, the Employee Hotline (which can be used on an anonymous basis where permitted by applicable law) or the Audit Committee. Ribbon established documentation and record maintenance mechanisms to ensure the retention of information relevant to the Company’s Conflict Minerals Policy electronically. OECD Guidance Step 2: Identify and Assess Risk in the Supply Chain Ribbon reviewed the information reported on the Template by its suppliers and followed up with any additional questions. To the extent an in-scope supplier had follow-up questions, Ribbon responded with all requested information, including part numbers and manufacturing lots to identify how the supplies were used in the Ribbon Products.

Ribbon Communications Inc. Conflict Minerals Report 2023 7 Untimely or incomplete responses as well as inconsistencies within the data reported by suppliers were addressed directly with respective suppliers to provide the required and/ or revised responses. Ribbon utilizes a series of escalating responses to address the failure of a supplier to provide the information required by the Template. Ribbon’s engineering, audit and legal departments manage the collection of information reported on the Template by its suppliers. Ribbon collected a list of smelters/processors that are in our supply chain for the Ribbon Products using the Template and reconciled this list to the list of smelter facilities designated by the Responsible Minerals Assurance Process (“RMAP”). Ribbon has provided that list in this report. Ribbon, through SiliconExpert, followed up with suppliers that did not respond initially to our requests to complete the Template. OECD Guidance Step 3: Design and Implement a Strategy to Respond to Identified Risks Ribbon adopted and used the Template to monitor and mitigate supply chain risk and took the steps described above. Ribbon worked with certain suppliers to better educate them on the Conflict Minerals process. Members of the Conflict Minerals team periodically report to senior management as well as the Audit Committee on program developments and progress. OECD Guidance Step 4: Carry Out Independent Third-Party Audit of Supply Chain Due Diligence Given that we do not generally have a direct relationship with the smelters and refineries that process the Conflict Minerals that are present in our Ribbon Products, we rely on the RMI to conduct audits of and validate the conflict-free status of smelters and refineries that source from Covered Countries. We have not relied on supplier representations concerning the conflict status of their smelters, but have required industry certification such as through the RMAP before concluding that a smelter or refinery is conflict free. We understand that this program is continuing to audit smelters and refineries to add to its Conflict-Free Smelter List. OECD Guidance Step 5: Report on Supply Chain Due Diligence As required by the Rule, we have filed a Form SD and a Conflict Minerals Report as an exhibit thereto for the 2023 calendar year reporting period. In accordance with OECD Guidance and the Rule, this report is available on our Investor Relations-Corporate Governance section of our website at: https://investors.ribboncommunications.com/ corporate-governance/governance-highlights.

Ribbon Communications Inc. Conflict Minerals Report 2023 8 Due Diligence Results Ribbon contacted 100% of a total of 852 in-scope suppliers (excluding distributors and service providers) for the 2023 Ribbon Products. Total in-scope suppliers contacted 852 Manufacturers providing CMRT documents/data 669 Manufacturers not providing CMRT responses 183 Overall response rate 78.5% The majority of the completed responses received provided conflict mineral data and a declaration at a “Company Level” (supplier/company declaration represents all the supplier’s products) or “Divisional Level” (supplier/company declaration represents all the supplier’s products from a division of the company). As a result, we are unable to determine whether any of the Conflict Minerals reported by the suppliers were contained in specific components or parts supplied to us with regard to Ribbon Products. Further, while our suppliers for the Ribbon Products identified certain of the smelters and refineries that provided Conflict Minerals, the responses did not provide specific information regarding the smelters or refineries of the Conflict Minerals in the particular components used in the 2023 Ribbon Products. Based on the responses we received from our suppliers, however, we believe the facilities used to produce the Conflict Minerals in the 2023 Ribbon Products may include the smelters and refineries listed in Annex A. In addition, based on the supplier responses, we believe the countries of origin of the Conflict Minerals in the 2023 Ribbon Products may include those listed in Annex B. 79% of in-scope suppliers provided responses to the CMRT survey.

Ribbon Communications Inc. Conflict Minerals Report 2023 9 560 626 486 Over the years, Ribbon has increased the pool of in-scope suppliers as business has expanded. Ribbon’s ability to secure responses from a greater number of suppliers is the result of consistent efforts to reach out to suppliers to educate them on the importance of conflict minerals management and secure full responses to our CMRT requests. MANUFACTURERS PROVIDING CMRTS OVERVIEW OF CMRT OUTREACH AND RESPONSE RATE 669 669 2019 2020 2021 2022 2023 Total Outreach Response Rate 2019 2020 2021 2022 2023 Based on the responses we received from our suppliers, however, we believe the facilities used to produce the Conflict Minerals in the 2023 Ribbon Products may include the smelters and refineries listed in Annex A. In 2023, we were successful in maintaining a strong response rate of 79%, a little higher than in 2022, representing a 7% increase in the number of suppliers responding, alongside a 6% increase in the number of suppliers we contacted. In addition, based on the supplier responses, we believe the countries of origin of the Conflict Minerals in the 2023 Ribbon Products may include those listed in Annex B. In 2023, the total number of in-scope manufacturers responding to Ribbon’s CMRT request was more than 660 manufacturers, a response rate of more than 78%, for the third consecutive year. 89% 858 83% 675 78% 805 78% 852 79% 546

Ribbon Communications Inc. Conflict Minerals Report 2023 10 Smelters in Our Supply Base SMELTERS BY METALS MINED Tantalum Tungsten Tin Gold SMELTERS BY COUNTRY Brazil Japan USA Indonesia Rest of World China Risk Mitigation Steps to Be Taken for 2024 Due Diligence Ribbon intends to take the following steps, as appropriate, during the next compliance period to further improve our due diligence process and results and to further mitigate the risk that our necessary Conflict Minerals benefit armed groups in the DRC or adjoining countries: Continue to focus on additional ways to improve quality and quantity of supplier response rates; Continue to work with suppliers to better educate them on the process; Continue to compare survey results to information collected via independent conflict free smelter validation programs such as the RMAP; Seek to implement standard procedures for corrective action or phasing out of suppliers not found to be DRC conflict free; Continue to adhere to the OECD Guidance; and Seek to work with suppliers who use appropriate due diligence methods and have continuous monitoring of both the direct and indirect supply chain to avoid procurement or use of Conflict Minerals. Audit An independent private sector audit was not required for reporting year 2023. 655 total smelters/ refiners from 57 countries with mines in133 countries 11% 14% 40% 35% 4% 7% 8% 37% 9% 35%

Ribbon Communications Inc. Conflict Minerals Report 2023 11 Important Information Regarding Forward-Looking Statements The information in this report contains “forward-looking statements” within the meaning of the U.S. Private Securities Litigation Reform Act of 1995, which are subject to a number of risks and uncertainties. All statements other than statements of historical facts contained in this report, including statements in the section “Risk Mitigation Steps to Be Taken for 2024 Due Diligence,” are forward-looking statements. Without limiting the foregoing, the words “anticipates”, “believes”, “could”, “estimates”, “expects”, “expectations”, “intends”, “may”, “plans”, “seeks”, “projects” and other similar language, whether in the negative or affirmative, are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Forward-looking statements are based on our current expectations and assumptions regarding our business, the economy and other future conditions. Because forward-looking statements relate to the future, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict. Ribbon therefore cautions readers against undue reliance on any of these forward-looking statements. Any forward-looking statement made by Ribbon in this report speaks only as of the date of this report. Ribbon undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future developments or otherwise, except as may be required by law. Documents Incorporated by Reference Unless otherwise stated herein, any documents, third party materials or references to websites (including Ribbon’s) are not incorporated by reference in, or considered to be a part of, this report unless expressly incorporated by reference herein.

Ribbon Communications Inc. Conflict Minerals Report 2023 12 Annex A List of Smelters We present in this report a list of smelters or refineries provided by those suppliers who completed the smelter list on our template, to the extent reasonably determinable, and that may have provided Conflict Minerals in any of the 2023 Ribbon Products. The table below includes only facilities, to the extent known, that have been validated by the RMI as facilities that are certified Conflict-Free or are listed on the Template as “known smelters or refineries.” Smelters and refineries that are denoted with an asterisk (*) in the table below have received a “conflict free” designation from an independent third party audit program. Tantalum (Ta) 5D Production OU Estonia Tin (Sn) 5N Plus United Kingdom Gold (Au) 8853 S.p.A. Italy Tungsten (W) A.L.M.T. Corp. Japan Tin (Sn) A.L.M.T. Corp. Japan Tungsten (W) A.L.M.T. Corp. China Gold (Au) ABC Refinery Pty Ltd. Australia Gold (Au) Abington Reldan Metals, LLC USA Gold (Au) Academy Precious Metals (China) Co. LTD China Tungsten (W) ACL Metais Eireli Brazil Gold (Au) Advanced Chemical Company USA Tantalum (Ta) Advanced Metallurgical Group N.V. (AMG) USA Gold (Au) African Gold Refinery Uganda Gold (Au) Agosi AG Germany Gold (Au) Aida Chemical Industries Co., Ltd. Japan Gold (Au) Aktyubinsk Copper Company TOO Kazakhstan Gold (Au) Al Etihad Gold Refinery DMCC United Arab Emirates Gold (Au) Al Ghaith Gold United Arab Emirates Tungsten (W) Albasteel Industria e Comercio de Ligas Para Fundicao Ltd. Brazil Gold (Au) Albino Mountinho Lda. Portugal Tin (Sn) Alent Alpha Metals (Shenzhen) Co., Ltd. China Gold (Au) Alexy Metals USA Gold (Au) Almalyk Mining and Metallurgical Complex (AMMC) Uzbekistan Tin (Sn) Alpha USA Tantalum (Ta) AMG Brasil Brazil Tantalum (Ta) AMG Mining Mibra Mine Brazil Substance Smelter Location

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 13 Tin (Sn) An Thai Minerals Co., Ltd. Vietnam Tin (Sn) An Vinh Joint Stock Mineral Processing Company Vietnam Tin (Sn) Angelcast Enterprise Co., Ltd. China Gold (Au) AngloGold Ashanti Corrego do Sitio Mineracao Brazil Tantalum (Ta) Anhui Herrman Impex Co. China Tin (Sn) Arco Alloys USA Gold (Au) Argor-Heraeus S.A. Switzerland Tungsten (W) Artek LLC Russian Federation Gold (Au) ARY Aurum Plus United Arab Emirates Gold (Au) Asahi Pretec Corp. Japan Gold (Au) Asahi Refining Canada Ltd. Canada Gold (Au) Asahi Refining USA Inc. USA Gold (Au) Asaka Riken Co., Ltd. Japan Tantalum (Ta) Asaka Riken Co., Ltd. Japan Tungsten (W) Asia Tungsten Products Vietnam Ltd. Vietnam Gold (Au) Atasay Kuyumculuk Sanayi Ve Ticaret A.S. Turkey Gold (Au) Attero Recycling Pvt Ltd India Gold (Au) AU Traders and Refiners South Africa Gold (Au) Augmont Enterprises Private Limited India Gold (Au) AURA-II USA Gold (Au) Aurubis AG Germany Tin (Sn) Aurubis Beerse Belgium Tin (Sn) Aurubis Berango Spain Tungsten (W) Avon Specialty Metals Ltd United Kingdom Tantalum (Ta) Avon Specialty Metals Ltd. United Kingdom Tin (Sn) Avtec USA Gold (Au) Baiyin Nonferrous Group Co.,Ltd China Gold (Au) Bangalore Refinery India Gold (Au) Bangko Sentral ng Pilipinas (Central Bank of the Philippines) Philippines Tin (Sn) Baoshan Iron & Steel Co., Ltd. China Gold (Au) Bauer Walser AG Germany Tungsten (W) BESEEM MINING CO., LTD. China Gold (Au) Boliden Ronnskar Sweden Tin (Sn) Brinkmann Chemie AG Germany

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 14 Gold (Au) C. Hafner GmbH + Co. KG Germany Gold (Au) C.I Metales Procesados Industriales SAS Colombia Gold (Au) Caridad Mexico Gold (Au) CCR Refinery - Glencore Canada Corporation Canada Gold (Au) Cendres + Metaux S.A. Switzerland Gold (Au) Central Bank of the DPR of Korea Korea, Democratic People's Republic of Tin (Sn) CFC Cooperativa dos Fundidores de Cassiterita da Amazonia Ltda. Brazil Gold (Au) CGR Metalloys Pvt Ltd. India Tantalum (Ta) Changsha South Tantalum Niobium Co., Ltd. China Gold (Au) Changsha South Tantalum Niobium Co., Ltd. China Gold (Au) Changzhou Chemical Research Institute Co. Ltd. China Tin (Sn) Chenzhou Yunxiang Mining and Metallurgy Co., Ltd. China Tin (Sn) Chifeng Dajingzi Tin Industry Co., Ltd. China Gold (Au) Chimet S.p.A. Italy Gold (Au) China Gold International Resources Corp. Ltd. China Gold (Au) China GoldDeal Investment Co., Ltd. China Tungsten (W) China Molybdenum Tungsten Co., Ltd. China Gold (Au) China National Gold Group Corporation China Tungsten (W) China National Nonferrous Metals Imp. & Exp. Jiangxi Co., Ltd. China Tin (Sn) China Tin Group Co., Ltd. China Tin (Sn) Chofu Works China Tungsten (W) Chongyi Zhangyuan Tungsten Co., Ltd. China Gold (Au) Chugai Mining Japan Tantalum (Ta) CMT Rare Metal Advanced Materials (Hunan) Co., Ltd. China Tungsten (W) CNMC (Guangxi) PGMA Co., Ltd. China Tin (Sn) CNMC (Guangxi) PGMA Co., Ltd. China Gold (Au) Codelco Chile Gold (Au) Coimpa Industrial LTDA Brazil Gold (Au) Colt Refining USA Tin (Sn) Cooperativa Metalurgica de Rondonia Ltda. Brazil Tungsten (W) CP Metals Inc. USA Tantalum (Ta) CP Metals Inc. USA

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 15 Tin (Sn) CRM Fundicao De Metais E Comercio De Equipamentos Eletronicos Do Brasil Ltda Brazil Tin (Sn) CRM Synergies Spain Tungsten (W) Cronimet Brasil Ltda Brazil Tin (Sn) CV Ayi Jaya Indonesia Tin (Sn) CV Dua Sekawan Indonesia Tin (Sn) CV Duta Putra Bangka Indonesia Tin (Sn) CV Gita Pesona Indonesia Tin (Sn) CV Makmur Jaya Indonesia Tin (Sn) CV United Smelting Indonesia Tin (Sn) CV Venus Inti Perkasa Indonesia Tantalum (Ta) D Block Metals, LLC USA Tin (Sn) Da Nang Processing Import and Export Joint Stock Vietnam Gold (Au) Daejin Indus Co., Ltd. Korea, Republic of Gold (Au) DaeryongENC Korea, Republic of Tin (Sn) Dai-ichi Seiko Japan Gold (Au) Dai-ichi Seiko Japan Gold (Au) Daye Non-Ferrous Metals Mining Ltd. China Tungsten (W) Dayu Jincheng Tungsten Industry Co., Ltd. China Tungsten (W) Dayu Weiliang Tungsten Co., Ltd. China Gold (Au) Degussa Sonne / Mond Goldhandel GmbH Germany Gold (Au) DHF Technical Products USA Gold (Au) Dijllah Gold Refinery FZC United Arab Emirates Tin (Sn) DingNan JiaWang HuanBao Co. LTD China Gold (Au) DODUCO Contacts And Refining Gmbh Germany Tin (Sn) Dong Guan Shi Xi Da Han Xi Product Co., Ltd China Tin (Sn) Dongguan CiEXPO Environmental Engineering Co., Ltd. China Tin (Sn) Dongguan City Xida Soldering Tin Products Co. China Gold (Au) Dongguan Standard Electronic Material Co., Ltd China Tungsten (W) DONGKUK INDUSTRIES CO., LTD. Korea, Republic of Gold (Au) Dongwu Gold Group China Tin (Sn) Dowa Japan Gold (Au) Dowa Japan Tin (Sn) Dragon Silver Holdings Limited China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 16 Tin (Sn) DS Myanmar Myanmar Gold (Au) DSC (Do Sung Corporation) Korea, Republic of Tantalum (Ta) Duoluoshan China Tantalum (Ta) E.S.R. Electronics USA Gold (Au) Eco-System Recycling Co., Ltd. East Plant Japan Gold (Au) Eco-System Recycling Co., Ltd. North Plant Japan Gold (Au) Eco-System Recycling Co., Ltd. West Plant Japan Tin (Sn) Electro-Mechanical Facility of the Cao Bang Minerals & Metallurgy Joint Stock Company Vietnam Gold (Au) Elemetal Refining, LLC USA Tin (Sn) Elemetal Refining, LLC USA Tin (Sn) EM Vinto Bolivia Gold (Au) Emerald Jewel Industry India Limited (Unit 1) India Gold (Au) Emerald Jewel Industry India Limited (Unit 2) India Gold (Au) Emerald Jewel Industry India Limited (Unit 3) India Gold (Au) Emerald Jewel Industry India Limited (Unit 4) India Gold (Au) Emirates Gold DMCC United Arab Emirates Tin (Sn) Estanho de Rondonia S.A. Brazil Tantalum (Ta) Exotech Inc. USA Tantalum (Ta) F&X Electro-Materials Ltd. China Tin (Sn) Fabrica Auricchio Industria e Comercio Ltda. Brazil Gold (Au) Faggi Enrico S.p.A. Italy Tin (Sn) Feinhutte Halsbrucke GmbH Germany Gold (Au) Feinhutte Halsbrucke GmbH Germany Tin (Sn) Fenix Metals Poland Gold (Au) Fidelity Printers and Refiners Ltd. Zimbabwe Tantalum (Ta) FIR Metals & Resource Ltd. China Gold (Au) Fujairah Gold FZC United Arab Emirates Tin (Sn) Fuji Metal Mining Corp. Japan Tungsten (W) Fujian Ganmin RareMetal Co., Ltd. China Tungsten (W) Fujian Jinxin Tungsten Co., Ltd. China Tungsten (W) Fujian Xinlu Tungsten Co., Ltd. China Tantalum (Ta) Gannon & Scott USA Tungsten (W) Ganxian Shirui New Material Co., Ltd. China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 17 Tungsten (W) Ganzhou Beseem Ferrotungsten Co., Ltd. China Tungsten (W) Ganzhou Haichuang Tungsten Co., Ltd. China Tungsten (W) Ganzhou Huaxing Tungsten Products Co., Ltd. China Tungsten (W) Ganzhou Jiangwu Ferrotungsten Co., Ltd. China Tungsten (W) Ganzhou Non-ferrous Metals Smelting Co., Ltd. China Tungsten (W) Ganzhou Seadragon W & Mo Co., Ltd. China Tungsten (W) Ganzhou Sunny Non-Ferrous Metals Co., Ltd. China Tungsten (W) Ganzhou Yatai Tungsten Co., Ltd. China Gold (Au) Geib Refining Corporation USA Tin (Sn) Gejiu City Fuxiang Industry and Trade Co., Ltd. China Tin (Sn) Gejiu Fengming Metallurgy Chemical Plant China Tin (Sn) Gejiu Jinye Mineral Company China Tin (Sn) Gejiu Kai Meng Industry and Trade LLC China Tin (Sn) Gejiu Non-Ferrous Metal Processing Co., Ltd. China Tin (Sn) Gejiu Yunxi Group Corp. China Tin (Sn) Gejiu Yunxin Nonferrous Electrolysis Co., Ltd. China Tin (Sn) Gejiu Zili Mining And Metallurgy Co., Ltd. China Gold (Au) GG Refinery Ltd. Tanzania Gold (Au) GGC Gujrat Gold Centre Pvt. Ltd. India Tantalum (Ta) Global Advanced Metals USA Tantalum (Ta) Global Advanced Metals Aizu Japan Tantalum (Ta) Global Advanced Metals Boyertown USA Tungsten (W) Global Tungsten & Powders LLC USA Tin (Sn) Gold Bell Group China Gold (Au) Gold by Gold Colombia Colombia Gold (Au) Gold Coast Refinery Ghana Gold (Au) Gold Refinery of Zijin Mining Group Co., Ltd. China Gold (Au) Great Wall Precious Metals Co., Ltd. of CBPM China Tin (Sn) Guangdong Hanhe Non-Ferrous Metal Co., Ltd. China Gold (Au) Guangdong Hua Jian Trade Co., Ltd. China Tin (Sn) Guangdong Jiatian Stannum Products Co., Ltd China Gold (Au) Guangdong Jinding Gold Limited China Gold (Au) Guangdong Jinxian Gaoxin Cai Liao Gong Si China Tantalum (Ta) Guangdong Rising Rare Metals-EO Materials Ltd. China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 18 Tungsten (W) Guangdong Xianglu Tungsten Co., Ltd. China Tin (Sn) Guangxi Hua Tin Gold Minute Fee, Ltd. China Tin (Sn) Guangxi Nonferrous Metals Group China Tin (Sn) Guangxi Zhongshan Jin Yi Smelting Co., Ltd. China Tin (Sn) Guanyang Guida Nonferrous Metal Smelting Plant China Tantalum (Ta) Guizhou Zhenhua Xinyun Technology Ltd., Kaili branch China Gold (Au) Guoda Safina High-Tech Environmental Refinery Co., Ltd. China Tin (Sn) Gwo Cherin Industrial Taiwan Gold (Au) Gwo Chern industrial Co., Ltd. Taiwan Tantalum (Ta) H.C. Starck GmbH Germany Tantalum (Ta) H.C. Starck GmbH Laufenburg Germany Tungsten (W) H.C. Starck Group Germany Tantalum (Ta) H.C. Starck Surface Technology and Ceramic Powders GmbH Germany Tungsten (W) H.C. Starck Tungsten GmbH Germany Gold (Au) Hang Seng Technology China Gold (Au) Hangzhou Fuchunjiang Smelting Co., Ltd. China Tungsten (W) Hannae For T Co., Ltd. Korea, Republic of Tin (Sn) Hayes Metals Pty Ltd New Zealand Gold (Au) Heimerle + Meule GmbH Germany Gold (Au) Henan Yuguang Gold & Lead Co., Ltd. China Tantalum (Ta) Hengyang King Xing Lifeng New Materials Co., Ltd. China Gold (Au) Heraeus Germany GmbH Co. KG Germany Gold (Au) Heraeus Metals Hong Kong Ltd. China Gold (Au) Hetai Gold Mineral Guangdong Co., Ltd. China Tin (Sn) Hezhou Jinwei Tin Co., Ltd. China Tin (Sn) HighTech Components Co., Ltd. Taiwan Tantalum (Ta) Hi-Temp Specialty Metals, Inc. USA Tin (Sn) Hongqiao Metals (Kunshan) Co., Ltd. China Gold (Au) Hop Hing electroplating factory Zhejiang China Tungsten (W) Hubei Green Tungsten Co., Ltd. China Tin (Sn) HuiChang Hill Tin Industry Co., Ltd. China Tin (Sn) Huichang Jinshunda Tin Co., Ltd. China Tin (Sn) HUIZHOU LIAN JING METAL MATERIAL CO.,LTD China Tin (Sn) Hulterworth Smelter China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 19 Tungsten (W) Hunan Chenzhou Mining Co., Ltd. China Gold (Au) Hunan Chenzhou Mining Co., Ltd. China Tungsten (W) Hunan Chuangda Vanadium Tungsten Co., Ltd. Wuji China Tungsten (W) Hunan Chuangda Vanadium Tungsten Co., Ltd. Yanglin China Gold (Au) Hunan Guiyang yinxing Nonferrous Smelting Co., Ltd. China Tungsten (W) Hunan Jintai New Material Co., Ltd. China Tungsten (W) Hunan Litian Tungsten Industry Co., Ltd. China Tungsten (W) Hunan Shizhuyuan Nonferrous Metals Co., Ltd. Chenzhou Tungsten Products Branch China Tin (Sn) Hunan Xianghualing Tin Co. ltd China Gold (Au) Hung Cheong Metal Manufacturing Limited China Gold (Au) HwaSeong CJ CO., LTD. Korea, Republic of Tungsten (W) Hydrometallurg, JSC Russian Federation Tin (Sn) IBF IND Brasileira de Ferroligas Ltda Brazil Tin (Sn) IMPAG AG Switzerland Tin (Sn) Incertec USA Gold (Au) Industrial Refining Company Belgium Gold (Au) Inner Mongolia Qiankun Gold and Silver Refinery Share Co., Ltd. China Gold (Au) International Precious Metal Refiners United Arab Emirates Gold (Au) I-PEX golden finger Japan Tin (Sn) I-PEX Inc. Japan Gold (Au) Ishifuku Metal Industry Co., Ltd. Japan Tin (Sn) Ishihara Chemical Co., Ltd. Japan Gold (Au) Istanbul Gold Refinery Turkey Gold (Au) Italpreziosi Italy Gold (Au) JALAN & Company India Gold (Au) Japan Mint Japan Tungsten (W) Japan New Metals Co., Ltd. Japan Tin (Sn) Jau Janq Enterprise Co., Ltd. Taiwan Tin (Sn) Jiang Jia Wang Technology Co. China Tin (Sn) Jiang Xi Jia Wang Technology Tin Products Environmental Ltd. China Tungsten (W) Jiangwu H.C. Starck Tungsten Products Co., Ltd. China Gold (Au) Jiangxi Copper Co., Ltd. China Tantalum (Ta) Jiangxi Dinghai Tantalum & Niobium Co., Ltd. China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 20 Tungsten (W) Jiangxi Gan Bei Tungsten Co., Ltd. China Tin (Sn) Jiangxi Ketai Advanced Material Co., Ltd. China Tungsten (W) Jiangxi Minmetals Gao'an Non-ferrous Metals Co., Ltd. China Tin (Sn) Jiangxi New Nanshan Technology Ltd. China Tungsten (W) Jiangxi Rare Earth & Rare Metals Tungsten Group Imp.& Exp. Co. Ltd. China Tungsten (W) Jiangxi Richsea New Materials Co., Ltd. China Tungsten (W) Jiangxi Tonggu Non-ferrous Metallurgical & Chemical Co., Ltd. China Tantalum (Ta) Jiangxi Tuohong New Raw Material China Tungsten (W) Jiangxi Xianglu Tungsten Co., Ltd. China Tungsten (W) Jiangxi Xinsheng Tungsten Industry Co., Ltd. China Tungsten (W) Jiangxi Xiushui Xianggan Nonferrous Metals Co., Ltd. China Tungsten (W) Jiangxi Yaosheng Tungsten Co., Ltd. China Tin (Sn) Jiangxi Yaosheng Tungsten Co., Ltd. China Gold (Au) Jin Jinyin Refining Co., Ltd. China Gold (Au) Jinlong Copper Co., Ltd. China Tantalum (Ta) Jiujiang Janny New Material Co., Ltd. China Tantalum (Ta) JiuJiang JinXin Nonferrous Metals Co., Ltd. China Tantalum (Ta) Jiujiang Tanbre Co., Ltd. China Tungsten (W) Jiujiang Tanbre Co., Ltd. China Tantalum (Ta) Jiujiang Zhongao Tantalum & Niobium Co., Ltd. China Tungsten (W) JSC "Kirovgrad Hard Alloys Plant" Russian Federation Gold (Au) JSC Ekaterinburg Non-Ferrous Metal Processing Plant Russian Federation Gold (Au) JSC Novosibirsk Refinery Russian Federation Gold (Au) JSC Uralelectromed Russian Federation Tin (Sn) Ju Tai Industrial Co., Ltd. China Gold (Au) JX Nippon Mining & Metals Co., Ltd. Japan Gold (Au) K.A. Rasmussen Norway Gold (Au) Kaloti Precious Metals United Arab Emirates Tin (Sn) KARAS PLATING LTD United Kingdom Gold (Au) Kazakhmys Smelting LLC Kazakhstan Gold (Au) Kazzinc Kazakhstan Tantalum (Ta) KEMET Blue Powder USA Tantalum (Ta) KEMET Corp. USA

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 21 Tantalum (Ta) KEMET de Mexico Mexico Tungsten (W) Kenee Mining Corporation Vietnam Vietnam Tungsten (W) Kennametal Fallon USA Tungsten (W) Kennametal Huntsville USA Gold (Au) Kennecott Utah Copper LLC USA Tungsten (W) KGETS Co., Ltd. Korea, Republic of Gold (Au) KGHM Polska Miedz Spolka Akcyjna Poland Tantalum (Ta) King-Tan Tantalum Industry Ltd. China Tin (Sn) Kobe Steel, Ltd. Japan Gold (Au) Kojima Chemicals Co., Ltd. Japan Gold (Au) Korea Metal Co., Ltd. Korea, Republic of Gold (Au) Korea Zinc Co., Ltd. Korea, Republic of Gold (Au) Kosak Seiren Japan Tin (Sn) Kovohute Pribram Nastupnicka, A.S. Czech Republic Gold (Au) KP Sanghvi International Pvt Ltd India Gold (Au) Kundan Care Products Ltd. India Gold (Au) Kunshan Jinli chemical industry reagents co.,Ltd. China Gold (Au) Kyrgyzaltyn JSC Kyrgyzstan Gold (Au) Kyshtym Copper-Electrolytic Plant ZAO Russian Federation Gold (Au) L'azurde Company For Jewelry Saudi Arabia Tin (Sn) LIAN JING China Tungsten (W) Lianyou Metals Co., Ltd. Taiwan Tungsten (W) Lianyou Resources Co., Ltd. Taiwan Gold (Au) Lingbao Gold Co., Ltd. China Gold (Au) Lingbao Jinyuan Tonghui Refinery Co., Ltd. China Tin (Sn) Linqu Xianggui Smelter Co., Ltd. China Tin (Sn) Linwu Xianggui Ore Smelting Co., Ltd. China Tungsten (W) LLC Vostok Russian Federation Gold (Au) L'Orfebre S.A. Andorra Gold (Au) LS MnM Inc. Korea, Republic of Gold (Au) LT Metal Ltd. Korea, Republic of Tin (Sn) Luna Smelter, Ltd. Rwanda Tungsten (W) Luoyang Mudu Tungsten & Molybdenum Technology Co., Ltd. China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 22 Gold (Au) Luoyang Zijin Yinhui Gold Refinery Co., Ltd. China Tin (Sn) M/s ECO Tropical Resources Singapore Tin (Sn) Ma An Shan Shu Guang Smelter Corp. China Tin (Sn) Ma On Shuguang Smelting Plant China Tin (Sn) Ma'anshan Weitai Tin Co., Ltd. China Tin (Sn) Magnu's Minerais Metais e Ligas Ltda. Brazil Tin (Sn) Malaysia Smelting Corporation (MSC) Malaysia Tin (Sn) Malaysia Smelting Corporation Berhad (Port Klang) Malaysia Tungsten (W) Malipo Haiyu Tungsten Co., Ltd. China Gold (Au) Marsam Metals Brazil Tungsten (W) Masan High-Tech Materials Vietnam Tin (Sn) Materials Eco-Refining Co., Ltd. Japan Gold (Au) Materials Eco-Refining CO.,LTD Japan Gold (Au) Materion USA Tantalum (Ta) Materion Newton Inc. USA Gold (Au) Matsuda Sangyo Co., Ltd. Japan Gold (Au) MD Overseas India Tin (Sn) Medeko Cast S.R.O. Slovakia Tungsten (W) Mehra Ferro-Alloys Pvt. Ltd. India Tin (Sn) Melt Metais e Ligas S.A. Brazil Tantalum (Ta) Meta Materials Macedonia Tin (Sn) Metahub Industries Sdn. Bhd. Malaysia Gold (Au) Metahub Industries Sdn. Bhd. Malaysia Gold (Au) Metal Concentrators SA (Pty) Ltd. South Africa Tin (Sn) Metallic Resources, Inc. USA Gold (Au) Metallix Refining Inc. USA Tin (Sn) Metallum Group Holding NV Belgium Tantalum (Ta) Metallurgical Products India Pvt., Ltd. India Gold (Au) Metalor Technologies (Hong Kong) Ltd. China Gold (Au) Metalor Technologies (Singapore) Pte., Ltd. Singapore Gold (Au) Metalor Technologies (Suzhou) Ltd. China Gold (Au) Metalor Technologies S.A. Switzerland Gold (Au) Metalor USA Refining Corporation USA Gold (Au) Metalurgica Met-Mex Penoles S.A. De C.V. Mexico

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 23 Tin (Sn) Minchali Metal Industry Co., Ltd. Taiwan Tin (Sn) Mineracao Taboca S.A. Brazil Tantalum (Ta) Mineracao Taboca S.A. Brazil Tin (Sn) Ming Li Jia smelt Metal Factory China Tin (Sn) Mining Minerals Resources SARL Congo, Democratic Republic of the Tin (Sn) Minmetals Ganzhou Tin Co. Ltd. China Tin (Sn) Minsur Peru Tin (Sn) Mitsubishi Materials Corporation Japan Gold (Au) Mitsubishi Materials Corporation Japan Tantalum (Ta) Mitsui Mining and Smelting Co., Ltd. Japan Gold (Au) Mitsui Mining and Smelting Co., Ltd. Japan Gold (Au) MK Electron Korea, Republic of Gold (Au) MKS PAMP SA Switzerland Gold (Au) MMTC-PAMP India Pvt., Ltd. India Tin (Sn) Modeltech Sdn Bhd Malaysia Gold (Au) Modeltech Sdn Bhd Malaysia Tungsten (W) Moliren Ltd. Russian Federation Gold (Au) Morris and Watson New Zealand Gold (Au) Morris and Watson Gold Coast Australia Gold (Au) Moscow Special Alloys Processing Plant Russian Federation Gold (Au) N.E. Chemcat Japan Gold (Au) Nadir Metal Rafineri San. Ve Tic. A.S. Turkey Tungsten (W) Nam Viet Cromit Joint Stock Company Vietnam Tungsten (W) Nanchang Cemented Carbide Limited Liability Company China Tantalum (Ta) Nantong Tongjie Electrical Co., Ltd. China Gold (Au) Navoi Mining and Metallurgical Combinat Uzbekistan Tin (Sn) Ney Metals and Alloys USA Tin (Sn) Nghe Tinh Non-Ferrous Metals Joint Stock Company Vietnam Gold (Au) NH Recytech Company Korea, Republic of Tungsten (W) Niagara Refining LLC USA Gold (Au) Nihon Material Co., Ltd. Japan Gold (Au) Nihon Superior Co., Ltd. Japan Tin (Sn) Nihon Superior Co., Ltd. China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 24 Tantalum (Ta) Ningxia Orient Tantalum Industry Co., Ltd. China Gold (Au) Nohon Material Corporation Japan Tin (Sn) Novosibirsk Tin Combine Russian Federation Tantalum (Ta) NPM Silmet AS Estonia Tungsten (W) NPP Tyazhmetprom LLC Russian Federation Gold (Au) Nyrstar Metals USA Tin (Sn) O.M. Manufacturing (Thailand) Co., Ltd. Thailand Tin (Sn) O.M. Manufacturing Philippines, Inc. Philippines Gold (Au) Ogussa Osterreichische Gold- und Silber-Scheideanstalt GmbH Austria Gold (Au) Ohura Precious Metal Industry Co., Ltd. Japan Gold (Au) OJSC "The Gulidov Krasnoyarsk Non-Ferrous Metals Plant" (OJSC Krastsvetmet) Russian Federation Gold (Au) OJSC Kolyma Refinery Russian Federation Tin (Sn) Old City Metals Processing Co., Ltd. China Tin (Sn) OMODEO A. E S. METALLEGHE SRL Italy Tungsten (W) OOO “Technolom” 1 Russian Federation Tungsten (W) OOO “Technolom” 2 Russian Federation Tin (Sn) Operaciones Metalurgicas S.A. Bolivia Tin (Sn) Pan Light Corporation Taiwan Gold (Au) Pease & Curren USA Gold (Au) Penglai Penggang Gold Industry Co., Ltd. China Tungsten (W) Philippine Chuangxin Industrial Co., Inc. Philippines Tin (Sn) Phoenix Metal Ltd. Rwanda Tungsten (W) Plansee Composite Materials GmbH Germany Tantalum (Ta) Plansee SE Austria Tantalum (Ta) Plansee SE Liezen Austria Tantalum (Ta) Plansee SE Reutte Austria Gold (Au) Planta Recuperadora de Metales SpA Chile Tantalum (Ta) PM Kalco Inc USA Tungsten (W) Pobedit, JSC Russian Federation Tin (Sn) Pongpipat Company Limited Myanmar Tantalum (Ta) Power Resources Ltd. Macedonia Tantalum (Ta) PowerX Ltd. Rwanda Gold (Au) Precious Metals Sales Corp. USA

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 25 Tin (Sn) Precious Minerals and Smelting Limited India Gold (Au) Prioksky Plant of Non-Ferrous Metals Russian Federation Tin (Sn) PSC VSMPO-AVISMA Corp. Russian Federation Tin (Sn) PT Alam Lestari Kencana Indonesia Gold (Au) PT Aneka Tambang (Persero) Tbk Indonesia Tin (Sn) PT Aries Kencana Sejahtera Indonesia Tin (Sn) PT Artha Cipta Langgeng Indonesia Tin (Sn) PT ATD Makmur Mandiri Jaya Indonesia Tin (Sn) PT Babel Inti Perkasa Indonesia Tin (Sn) PT Babel Surya Alam Lestari Indonesia Tin (Sn) PT Bangka Kudai Tin Indonesia Tin (Sn) PT Bangka Prima Tin Indonesia Tin (Sn) PT Bangka Putra Karya Indonesia Tin (Sn) PT Bangka Serumpun Indonesia Tin (Sn) PT Bangka Timah Utama Sejahtera Indonesia Tin (Sn) PT Bangka Tin Industry Indonesia Tin (Sn) PT Belitung Industri Sejahtera Indonesia Tin (Sn) PT BilliTin Makmur Lestari Indonesia Tin (Sn) PT Bukit Timah Indonesia Tin (Sn) PT Cipta Persada Mulia Indonesia Tin (Sn) PT DS Jaya Abadi Indonesia Tin (Sn) PT Eunindo Usaha Mandiri Indonesia Tin (Sn) PT Fang Di MulTindo Indonesia Tin (Sn) PT HP Metals Indonesia Indonesia Tin (Sn) PT Inti Stania Prima Indonesia Tin (Sn) PT Justindo Indonesia Tin (Sn) PT Karimun Mining Indonesia Tin (Sn) PT Kijang Jaya Mandiri Indonesia Tin (Sn) PT Koba Tin Indonesia Tin (Sn) PT Lautan Harmonis Sejahtera Indonesia Tin (Sn) PT Masbro Alam Stania Indonesia Tin (Sn) PT Menara Cipta Mulia Indonesia Tin (Sn) PT Mitra Stania Prima Indonesia Tin (Sn) PT Mitra Sukses Globalindo Indonesia

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 26 Tin (Sn) PT NATARI Indonesia Tin (Sn) PT O.M. Indonesia Indonesia Tin (Sn) PT Panca Mega Persada Indonesia Tin (Sn) PT Premium Tin Indonesia Indonesia Tin (Sn) PT Prima Timah Utama Indonesia Tin (Sn) PT Putera Sarana Shakti (PT PSS) Indonesia Tin (Sn) PT Rajawali Rimba Perkasa Indonesia Tin (Sn) PT Rajehan Ariq Indonesia Tin (Sn) PT Refined Bangka Tin Indonesia Tin (Sn) PT Sariwiguna Binasentosa Indonesia Tin (Sn) PT Stanindo Inti Perkasa Indonesia Tin (Sn) PT Sukses Inti Makmur (SIM) Indonesia Tin (Sn) PT Sumber Jaya Indah Indonesia Tin (Sn) PT Supra Sukses Trinusa Indonesia Tin (Sn) PT Timah Nusantara Indonesia Tin (Sn) PT Timah Tbk Indonesia Tin (Sn) PT Timah Tbk Kundur Indonesia Tin (Sn) PT Timah Tbk Mentok Indonesia Tin (Sn) PT Tinindo Inter Nusa Indonesia Tin (Sn) PT Tirus Putra Mandiri Indonesia Tin (Sn) PT Tommy Utama Indonesia Tin (Sn) PT Wahana Perkit Jaya Indonesia Tin (Sn) PT Yinchendo Mining Industry Indonesia Gold (Au) PX Precinox S.A. Switzerland Gold (Au) QG Refining, LLC USA Tantalum (Ta) QSIL Metals Hermsdorf GmbH Germany Tantalum (Ta) QuantumClean USA Gold (Au) Rand Refinery (Pty) Ltd. South Africa Gold (Au) Realized the Enterprise Co., Ltd. China Tin (Sn) RedRing Solder (M) Sdn. Bhd Malaysia Gold (Au) Refinery of Seemine Gold Co., Ltd. China Gold (Au) REMONDIS PMR B.V. Netherlands Gold (Au) Republic Metals Corporation USA Tin (Sn) Resind Industria e Comercio Ltda. Brazil

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 27 Tantalum (Ta) Resind Industria e Comercio Ltda. Brazil Tantalum (Ta) RFH Recycling Metals Co., Ltd. China Tantalum (Ta) RFH Yancheng Jinye New Material Technology Co., Ltd. China Tin (Sn) Rian Resources SDN. BHD. Malaysia Gold (Au) Rio Tinto Group Australia Gold (Au) Royal Canadian Mint Canada Tin (Sn) Rui Da Hung Taiwan Gold (Au) SAAMP France Gold (Au) Sabin Metal Corp. USA Gold (Au) Safimet S.p.A Italy Gold (Au) SAFINA A.S. Czechia Gold (Au) Sai Refinery India Gold (Au) Sam Precious Metals United Arab Emirates Gold (Au) Samduck Precious Metals Korea, Republic of Tin (Sn) Samhwa non-ferrorus Metal ind.co.ltd Korea, Republic of Gold (Au) Samwon Metals Corp. Korea, Republic of Gold (Au) Sancus ZFS (L’Orfebre, SA) Colombia Tungsten (W) Sanher Tungsten Vietnam Co., Ltd. Vietnam Gold (Au) Sanmenxia Hengsheng science and technology, research and development Co., LTD China Gold (Au) Saxonia Edelmetalle GmbH Germany Gold (Au) Schone Edelmetaal B.V. Netherlands Gold (Au) ScotiaMocatta, The Bank of Nova Scotia Hong Kong Gold (Au) Sellem Industries Ltd. Mauritania Gold (Au) SEMPSA Joyeria Plateria S.A. Spain Gold (Au) Shan Dong Huangjin China Tin (Sn) Shan Tou Shi Yong Yuan Jin Shu Zai Sheng Co., Ltd. China Gold (Au) Shan Tou Shi Yong Yuan Jin Shu Zai Sheng Co., Ltd. China Gold (Au) Shandon Jin Jinyin Refining Limited China Gold (Au) Shandong Gold Smelting Co., Ltd. China Gold (Au) Shandong Hengbang Smelter Co., Ltd. China Gold (Au) Shandong Humon Smelting Co., Ltd. China Gold (Au) Shandong penglai gold smelter China Gold (Au) Shandong Tiancheng Biological Gold Industrial Co., Ltd. China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 28 Gold (Au) Shandong Yanggu Xiangguang Co., Ltd. China Gold (Au) Shandong Zhaojin Gold & Silver Refinery Co., Ltd. China Gold (Au) Shandong Zhongkuang Group Co.,Ltd. China Tantalum (Ta) Shanghai Jiangxi Metals Co., Ltd. China Tin (Sn) ShangHai YueQiang Metal Products Co., LTD China Tin (Sn) Shangrao Xuri Smelting Factory China Tin (Sn) Shen Mao Solder (M) Sdn. Bhd Taiwan Gold (Au) Shenzhen CuiLu Gold Co., Ltd. China Gold (Au) Shenzhen Heng Zhong Industry Co., Ltd. China Tin (Sn) Shenzhen Hong Chang Metal Manufacturing Factory China Tin (Sn) Shenzhen Yi Cheng Industrial China Gold (Au) Shenzhen Zhonghenglong Real Industry Co., Ltd. China Tungsten (W) Shinwon Tungsten (Fujian Shanghang) Co., Ltd. China Gold (Au) Shirpur Gold Refinery Ltd. India Tin (Sn) Sichuan Guanghan Jiangnan casting smelters China Gold (Au) Sichuan Tianze Precious Metals Co., Ltd. China Tin (Sn) Sigma Tin Alloy Co., Ltd. China Gold (Au) Singway Technology Co., Ltd. Taiwan Gold (Au) Sino-Platinum Metals Co., Ltd. China Tin (Sn) Sizer Metals PTE Ltd Singapore Gold (Au) So Accurate Group, Inc. USA Gold (Au) SOE Shyolkovsky Factory of Secondary Precious Metals Russian Federation Tin (Sn) Soft Metais Ltda. Brazil Gold (Au) Solar Applied Materials Technology Corp. Taiwan Tin (Sn) Solder Court Ltd China Tin (Sn) Solder Court Ltd. China Tantalum (Ta) Solikamsk Magnesium Works OAO Russian Federation Tungsten (W) South-East Nonferrous Metal Company Limited of Hengyang City China Gold (Au) Sovereign Metals India Tin (Sn) Spectro Alloys Corp. USA Gold (Au) Standard Bank USA Gold (Au) State Research Institute Center for Physical Sciences and Technology Lithuania

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 29 Gold (Au) Success Technology (Shenzhen) Co., Ltd. China Gold (Au) Sudan Gold Refinery Sudan Gold (Au) Sumitomo Metal Mining Co., Ltd. Japan Gold (Au) SungEel HiMetal Co., Ltd. Korea, Republic of Gold (Au) Suntain Co., Ltd. Taiwan Gold (Au) Super Dragon Technology Co., Ltd. Taiwan Tin (Sn) Super Ligas Brazil Tin (Sn) Suzhou Nuonengda Chemical Co., Ltd. China Gold (Au) SuZhou ShenChuang recycling Ltd. China Gold (Au) Suzhou Xingrui Noble Metal Material Co., Ltd. China Gold (Au) T.C.A S.p.A Italy Tungsten (W) TaeguTec Korea, Republic of Gold (Au) Tai Perng Indonesia Gold (Au) Tai zhou chang san Jiao electron Co.,Ltd China Tin (Sn) Taicang City Nancang Metal Material Co., Ltd. China Tantalum (Ta) Taike Technology (Suzhou) Co.,Ltd. China Tin (Sn) Taiwan high-tech Co., Ltd. Taiwan Tin (Sn) Taiwan Huanliang Taiwan Gold (Au) Taiwan Totai Co., Ltd. Taiwan Tin (Sn) Taiwan's lofty Enterprises Ltd. Taiwan Tin (Sn) Takehara PVD Materials Plant / PVD Materials Division of Mitsui Mining & Smelting Co., Ltd. Japan Tantalum (Ta) Taki Chemical Co., Ltd. Japan Tin (Sn) Tamura Japan Gold (Au) Tanaka Kikinzoku Kogyo K.K. Japan Tantalum (Ta) Taniobis Co., Ltd. Thailand Tantalum (Ta) Taniobis GMBH Germany Tantalum (Ta) Taniobis Japan Co., Ltd. Japan Tungsten (W) Taniobis Smelting GMBH & Co. Kg Germany Tantalum (Ta) Taniobis Smelting GMBH & Co. Kg Germany Tantalum (Ta) Tantalite Resources South Africa Tungsten (W) Tejing (Vietnam) Tungsten Co., Ltd. Vietnam Tantalum (Ta) Telex Metals USA Tin (Sn) Tennessee Aluminum Processors USA

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 30 Tin (Sn) Thai Nguyen Mining and Metallurgy Co., Ltd. Vietnam Tin (Sn) Thailand Mine Factory Thailand Tin (Sn) Thaisarco Thailand Tin (Sn) Three green surface technology limited company China Tin (Sn) Tianshui Ling Bo Technology Co., Ltd. China Tin (Sn) TIN PLATING GEJIU China Tin (Sn) Tin Smelting Branch of Yunnan Tin Co., Ltd. China Tin (Sn) Tin Technology & Refining USA Gold (Au) Tokuriki Honten Co., Ltd. Japan Tin (Sn) TONG LONG China Tin (Sn) Tongding Metal Material Co., Ltd. China Gold (Au) Tongling Nonferrous Metals Group Co., Ltd. China Gold (Au) TOO Tau-Ken-Altyn Kazakhstan Tin (Sn) Top-Team Technology (Shenzhen) Ltd. China Gold (Au) Torecom Korea, Republic of Tantalum (Ta) Tranzact, Inc. USA Tin (Sn) TRATHO Metal Quimica Brazil Gold (Au) Tsai Brother industries Taiwan Gold (Au) TSK Pretech Korea, Republic of Tungsten (W) Tungsten Diversified Industries LLC USA Tungsten (W) Tungsten Vietnam Joint Stock Company Vietnam Tin (Sn) Tuyen Quang Non-Ferrous Metals Joint Stock Company Vietnam Tantalum (Ta) Ulba Metallurgical Plant JSC Kazakhstan Tin (Sn) Ultracore Co., Ltd. Thailand Tantalum (Ta) ULVAC Inc. Japan Gold (Au) Umicore Brasil Ltda. Brazil Gold (Au) Umicore Precious Metals Thailand Thailand Gold (Au) Umicore S.A. Business Unit Precious Metals Refining Belgium Tungsten (W) Unecha Refractory metals plant Russian Federation Gold (Au) United Precious Metal Refining, Inc. USA Gold (Au) Universal Precious Metals Refining Zambia Zambia Tantalum (Ta) V&D New Materials (Jiangsu) Co., Ltd. China Gold (Au) Valcambi S.A. Switzerland Gold (Au) Value Trading Belgium

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 31 Gold (Au) Viagra Di precious metals (Zhaoyuan) Co., Ltd. China Tungsten (W) Vietnam Youngsun Tungsten Industry Co., Ltd. Vietnam Tin (Sn) VQB Mineral and Trading Group JSC Vietnam Gold (Au) Wang Ting China Gold (Au) Weeerefining France Tin (Sn) Welley Taiwan Gold (Au) Western Australian Mint (T/a The Perth Mint) Australia Tin (Sn) Westfalenzinn Germany Tin (Sn) Westmetall GmbH & Co. KG Germany Tin (Sn) White Solder Metalurgia e Mineracao Ltda. Brazil Gold (Au) WIELAND Edelmetalle GmbH Germany Tungsten (W) Wolfram Bergbau und Hutten AG Austria Tungsten (W) WOLFRAM Company CJSC Russian Federation Tungsten (W) Woltech Korea Co., Ltd. Korea, Republic of Tin (Sn) Wujiang City Luxe Tin Factory China Tin (Sn) Wuxi Yunxi Sanye Solder Factory China Gold (Au) Wuzhong Group China Tin (Sn) Xiamen Honglu Tungsten Molybdenum Co., Ltd. China Gold (Au) Xiamen JInbo Metal Co., Ltd. China Tungsten (W) Xiamen Tungsten (H.C.) Co., Ltd. China Tungsten (W) Xiamen Tungsten Co., Ltd. China Tin (Sn) XiaMen YiQuan Precision Metal Co., Ltd China Tin (Sn) Xianghualing Tin Industry Co., Ltd. China Tantalum (Ta) Ximei Resources (Guangdong) Limited China Tantalum (Ta) Ximei Resources(Guizhou) Technology Co., Ltd. China Tin (Sn) Xin Furukawa Metal ( Wuxi ) Co., Ltd. China Tungsten (W) Xinfeng Huarui Tungsten & Molybdenum New Material Co., Ltd. China Tungsten (W) Xinhai Rendan Shaoguan Tungsten Co., Ltd. China Tantalum (Ta) XinXing HaoRong Electronic Material Co., Ltd. China Tin (Sn) XURI China Gold (Au) Yamakin Co., Ltd. Japan Gold (Au) Yamato Denki Ind. Co., Ltd. Japan Tantalum (Ta) Yanling Jincheng Tantalum & Niobium Co., Ltd. China Gold (Au) Yantai Zhaojin Kanfort Precious Metals Incorporated Company China

Substance Smelter Location Ribbon Communications Inc. Conflict Minerals Report 2023 32 Tantalum (Ta) Yichun Jin Yang Rare Metal Co., Ltd. China Tin (Sn) Yifeng Tin China Tin (Sn) Yiquan Manufacturing China Gold (Au) Yokohama Metal Co., Ltd. Japan Tungsten (W) Yudu Ansheng Tungsten Co., Ltd. China Tin (Sn) Yuecheng Tin Co., Ltd. China Tin (Sn) Yunnan Chengfeng Non-ferrous Metals Co., Ltd. China Tin (Sn) Yunnan Chengo Electric Smelting Plant China Gold (Au) Yunnan Copper Industry Co., Ltd. China Tin (Sn) Yunnan Copper Zinc Industry Co., Ltd. China Tin (Sn) Yunnan Geiju Smelting Corp. China Gold (Au) Yunnan Gold Mining Group Co., Ltd. (YGMG) China Tin (Sn) Yunnan Industrial Co., Ltd. China Tin (Sn) Yunnan Malipo Baiyi Kuangye Co. China Gold (Au) Yunnan Metallurgical Group Co., Ltd China Tin (Sn) yunnan xi ye gufen youxian gongsi China Tin (Sn) Yunnan Yunfan Non-ferrous Metals Co., Ltd. China Tungsten (W) Zhangzhou Chuen Bao Apt Smeltery Co., Ltd. China Gold (Au) Zhaojun Maifu China Gold (Au) Zhe Jiang Guang Yuan Noble Metal Smelting Factory China Gold (Au) Zhongkuang Gold Industry Co., Ltd. China Gold (Au) Zhongshan Hyper-Toxic Substance Monopolized Co., Ltd. China Tin (Sn) Zhongshan Jinye Smelting Co.,Ltd China Gold (Au) Zhongshan Poison Material Proprietary Co., Ltd. China Gold (Au) Zhongyuan Gold Smelter of Zhongjin Gold Corporation China Tin (Sn) Zhuhai Horyison Solder Co., Ltd. China Gold (Au) Zhuhai Toxic Materials Monopoly Ltd. China Gold (Au) Zhuzhou Cemented Carbide China Tungsten (W) Zhuzhou Cemented Carbide Group Co., Ltd. China Tantalum (Ta) Zhuzhou Cemented Carbide Group Co., Ltd. China Gold (Au) Zhuzhou Smelting Group Co., Ltd China

Ribbon Communications Inc. Conflict Minerals Report 2023 33 Countries of origin of the Conflict Minerals in the 2023 Ribbon Products are believed to include: Afghanistan El Salvador Libya Saudi Arabia Albania Eritrea Liechtenstein Senegal Andorra Estonia Lithuania Serbia Angola Ethiopia Luxembourg Sierra Leone Argentina Finland Madagascar Singapore Armenia France Malawi Slovakia Australia Gabon Malaysia Slovenia Austria Gambia Mali Solomon Islands Azerbaijan Georgia Malta South Africa Belarus Germany Mauritania Spain Belgium Ghana Mauritius Sudan Benin Greece Mexico Suriname Bermuda Guatemala Mongolia Sweden Bolivia Guinea Morocco Switzerland Botswana Guyana Mozambique Taiwan Brazil Honduras Myanmar Tajikistan Bulgaria Hong Kong Namibia Tanzania Burkina Faso Hungary Netherlands Thailand Burundi India New Zealand Togo Cambodia Indonesia Nicaragua Tunisia Cameroon Ireland Niger Turkey Canada Israel Nigeria Uganda Central African Republic Italy Norway United Arab Emirates Chile Ivory Coast Oman United Kingdom China Japan Pakistan United States of America Colombia Jordan Panama Uruguay Croatia Kazakhstan Peru Uzbekistan Cyprus Kenya Philippines Vietnam Czech Republic Korea Poland Yemen Democratic Republic of Congo Kuwait Portugal Zambia Denmark Kyrgyzstan Romania Zimbabwe Dominican Republic Latvia Russian Federation Ecuador Lebanon Rwanda Egypt Liberia San Marino Annex B List of Countries Location of Mines: 133 countries