 Market-leading offer optimized for metro and long-haul applications PLANO, Texas, June 1, 2021 PRNewswire -- Ribbon Communications Inc. Nasdaq: RBBN, a global provider of real time communications software and IP optical networking solutions to service providers, enterprises, and critical infrastructure sectors, today announced its new TM400_2 line card. Part of the Apollo optical networking portfolio, the TM400_2 leverages 400G ZR, a disruptive technology that incorporates pluggables to deliver improved economics and flexibility. 