Upgrade your DECT Phone/regular phone to a PSTN/VoIP Dual Mode phone. The standby mode is on PSTN channel (Necessary for emergency calls such as 911) Call Hold FSK Caller ID Auto Reply One FXS port, one PSTN port for pass-thru l Power Indicator & VoIP Indicator Seamlessly integrated with X-TAPI Lite/Pro and BeyondTel's SIP Softphone