A trunk is a logical link between two exchange offices. Inter-office calls must be transmitted by trunks. The device supports the following trunk modes:
A PRA trunk is connected to a VE1 interface and is usually used to connect two PBXs.
An AT0 trunk is connected to an FXO interface for accessing the PSTN network. The PBX enterprise needs to use the AT0 trunk for making calls to non-enterprise numbers or making long-distance fixed-line calls.
A SIP trunk is established on an IP link and connects a PBX and an IMS. There are two types of SIP trunks: SIP AT0 trunk and common SIP trunk.
The E1R2 trunk is bound to VE1 interfaces and is usually used to connect two PBXs. The E1R2 trunk can be connected to a peer device using R2 signaling.
The device supports the E1R2 trunk from V200R002C00.
An H323 trunk is established on an IP link. It connects a PBX and an IMS or connects PBXs in different areas.
The device supports the H323 trunk from V200R002C01.
A BRA trunk is bound to a BRA interface and connects a PBX and an ISDN.
The device supports the BRA trunk from V200R002C02.