RBBN - Ribbon Communications Inc. (RBBN) Q1 2021 Earnings Call Transcript April, 29 2021 01:31 AM Ribbon Communications Inc. Image source: The Motley Fool. Ribbon Communications Inc. (NASDAQ: RBBN) Q1 2021 Earnings Call Apr 28, 2021 , 4:30 p.m. ET Operator Continue reading For further details see: Ribbon Communications Inc. (RBBN) Q1 2021 Earnings Call Transcript