#1Adtran Adtran Holdings November 06, 2023 Investor presentation#2Cautionary note regarding forward-looking statements Statements contained in this presentation which are not historical facts, such as those relating to expectations regarding earnings, expenses and margin; the ability of ADTRAN Holdings, Inc. ("ADTRAN Holdings") to reduce expenses in the coming year and the amount there of through its implementation of the business efficiency program; and ADTRAN Holdings' strategy, outlook and financial guidance, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can also generally be identified by the use of words such as "believe," "expect," "intend," "estimate," "anticipate," "will," "may," "could" and similar expressions. In addition, ADTRAN Holdings, through its senior management, may from time to time make forward-looking public statements concerning the matters described herein. All such projections and other forward-looking information speak only as of the date hereof, and ADTRAN Holdings undertakes no duty to publicly update or revise such forward-looking information, whether as a result of new information, future events, or otherwise, except to the extent as may be required by law. All such forward-looking statements are necessarily estimates and reflect management's best judgment based upon current information. Actual events or results may differ materially from those anticipated in these forward-looking statements as a result of a variety of factors. While it is impossible to identify all such factors, factors which have caused and may in the future cause actual events or results to differ materially from those estimated by ADTRAN Holdings include, but are not limited to: (i) risks and uncertainties related to manufacturing and supply chain constraints; (ii) risks and uncertainties related to the completed business combination between the Company, ADTRAN, Inc. ("ADTRAN") and Adtran Networks SE ("Adtran Networks"), including risks related to the ability to successfully integrate ADTRAN's and Adtran Networks' businesses, the disruption of management time from ongoing business operations due to integration efforts following the business combination, and the risk that ADTRAN Holdings may be unable to achieve expected synergies or that it may take longer or be more costly than expected to achieve those synergies; (iii) risks and uncertainties relating to the recent restatement of our previously issued consolidated financial statements and ongoing material weakness in our internal control over financial reporting; (iv) risks and uncertainties relating to ADTRAN Holdings' ability to reduce expenditures and the impact of such reductions on its financial results and financial condition; (v) the risk of fluctuations in revenue due to lengthy sales and approval processes required by major and other service providers for new products, as well as ongoing tighter inventory management of ADTRAN Holdings' customers; (vi) the risk posed by potential breaches of information systems and cyber-attacks; (vii) the risk that ADTRAN Holdings may not be able to effectively compete, including through product improvements and development; and (viii) other risks set forth in ADTRAN Holdings' public filings made with the Securities and Exchange Commission, including its Annual Report on Form 10-K for the year ended December 31, 2022, as amended, as well as its Form 10-Q for the quarter ended June 30, 2023 2 2023 ADTRAN, INC. Adtran#3Introduction and business model 3#4Your trusted partner for the fiber everywhere era $1.25B Key differentiators Open, disaggregated platforms with vendor-neutral capability Extensive global design support and supply orchestration capabilities (Supply chain) 4 FY22 revenue Global top 3 supplier A-Q 50 A Worldwide locations HQ = Huntsville, AL 2023 ADTRAN, INC. 1.000+ End-to-end solutions portfolio patents Ⓒ Global technology 3.300+ Employees worldwide 35+ Years of experience Ypr ● Customers = NSPs, RSPS, ASPs, SMBS, enterprises, tribal communities, governments and agencies: local, state, federal Simplified pricing structure "Adtran is focused on customer usability, service and support." Tom Stanton, CEO, Adtran Adtran#55 2023 © ADTRAN, INC. OUR VISION is to enable a fully-connected world, where the power and freedom to communicate is available to everyone, everywhere, in a secure, efficient and sustainable environment.#6Global presence Americas: Canada United States (HQ Global) Brazil EMEA: Germany (HQ Europe) England Switzerland Poland Finland Sweden France Italy Israel South Africa Saudi Arabia APAC: Japan China Hong Kong Singapore India Australia#7Adtran is a global vendor with scale and diversity 7 ● ● A Portfolio Differentiation Optical core to customer premise End-to-end automation & insights Enhanced security and assurance 2023 ADTRAN, INC. ● ● WWW Customer Diversity More balanced mix of national SPs, regional SPs, enterprise, and ICP customers Continued growth opportunities in each segment Geographic Diversity Balanced mix of U.S. and non-U.S. business Strong growth opportunities in focus regions Strength in Focus Markets Full range of R&D, pre- sales, post-sales and services support in focus regions Strong market share in growth products in focus regions Adtran#8Management board 8 ● ● Tom Stanton Chairman & CEO Joined Adtran in 1995 as VP of Marketing for the Carrier Networks Division and named Adtran's CEO in September 2005 and Chairman of the Board in 2007 Holds a Bachelor of Science in Computer Engineering from Auburn University 2023 ADTRAN, INC. . ● Christoph Glingener CTO Joined ADVA Optical Networking in April 2006, appointed CTO in 2007 and named CTO of Adtran in September 2022 Holds Ph.D in Electric Engineering from the University of Dortmund ● ● Uli Dopfer CFO Joined ADVA Optical Networking in March 2004, appointed CFO in January 2015 and named CFO of Adtran in May 2023 Holds a Diploma in business economics from Wirtschafts- akademie Munich, Germany Jay Wilson CRO Joined Adtran in 1998 and has held many roles from Senior Vice President of Technology and Strategy to GM of Adtran's Carrier Networks Division, VP of Product Marketing, Holds a Bachelor of Engineering in Electrical Engineering from Vanderbilt University Adtran#9Optical core to customer premise Smart 9 ==== lo T 2023 ADTRAN, INC. Subscriber Platforms Subscriber Solutions Al-driven Orchestration, Management and Optimization Software Platforms Fiber Access & Aggregation Platforms Access & Aggregation Deployment & Support Services O Metro WDM LELB Optical Platforms DCI Optical Networking BBC BA BB Adtran#10Our portfolio Cliff & Subscriber and enterprise solutions Open multi-gig PON systems, Carrier Ethernet access, Wi-Fi, IoT, routers, switches and more Access and aggregation solutions Fiber access platforms, 1/10/25/100G Ethernet aggregation, network timing and synchronization Optical Networking Solutions Optical access and transport, data center interconnect, advanced pluggable optics, assurance and monitoring, encryption and security 10 2023 ADTRAN, INC. Software platforms Open, cloud- centric management and orchestration Professional services Scalable in- region services, including planning, deployment, and maintenance Adtran#11Revenue categories and product examples 11 Subscriber Solutions SDX 630 Adtran Wi-Fi 6, 6E, & 7 mesh gateways (SDGs) 2023 ADTRAN, INC. Access & Aggregation SDX 6330 ******************** FSP 150 Optical Networking FSP 3000 CIXDIO: BODIE Coherent 100 ZR PADVA Adtran