Compatible if correct firmware version is used. May require settings change
This family of routers will work well with VOIP services so long as the firmware version on the unit is v4.2.1.02. Other versions may cause issues. The MTU settings under ‘Setup’ -> ‘Network’ should be set to 1500 (Cable) or 1492 (DSL). If this router has issues with phones not ringing, the issue may be UDP sessions being closed early. Our staff have resolved this by upgrading to 4.2.1.02 firmware, then going to the hidden page at https://(router LAN IP)/f_general_hidden.htm and then changing the UDP Timeout from 30 seconds to 300 seconds.