What Is the SIP AT0 Trunk?
The local device uses SIP to connect to the peer device through the SIP AT0 trunk over the IP network.
PBX users can use SIP AT0 trunks to perform SIP calls or other applications through the IMS or softswitch. One SIP AT0 trunk can be used by only one user at a time. Incoming calls over the SIP AT0 trunk are forwarded to the local device or switchboard by default.