X0306 4 2022-03-15 0001708055 Ribbon Communications Inc. RBBN 0001600024 LOPEZ MIGUEL A C/O RIBBON COMMUNICATIONS INC. 6500 CHASE OAKS BOULEVARD, SUITE 100 PLANO TX 75023 0 1 0 0 EVP, CFO Common Stock 2022-03-15 4 P 0 3000 2.97 A 88975 D Common Stock 2022-03-15 4 M 0 17922 A 103897 D Common Stock 2022-03-15 4 F 0 6370 2.81 D 97527 D Restricted Stock Units (RSU) 2022-03-15 4 M 0 17922 0 D Common Stock 17922 35842 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.96 to $2.98, inclusive. The reporting person undertakes to provide to Ribbon, any security holder of Ribbon, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price with the ranges set forth in this footnote. RSUs convert to common stock on a one-for-one basis. Reflects shares of Common Stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of RSUs. The RSUs vest over a three-year period as follows: one-third of the restricted stock units vested on March 15, 2022, and the remaining two-thirds of the RSUs shall vest in four equal, semi-annual installments thereafter through March 15, 2024. Patrick Macken, Attorney-in-Fact 2022-03-16