Call4tel

M1 SIP Trunk Configuration with NX32

M1 is a major Singapore communications provider. Using an M1 SIP trunk with 3CX requires a dedicated second network card routing traffic between the 3CX server and M1's servers. Requires 3CX version 15.5 or later, plus M1-provided DIDs, SIP server IP, and WAN IP.

  1. Configure dual network cards: WAN for internet/extensions via the primary NX32, LAN dedicated to M1 traffic only.
  2. Add a static route via SIP Connect in the Call4tel portal using the gateway IP M1 provided.
  3. Manually configure the M1 WAN IP on the LAN interface per M1's instructions.
  4. In the 3CX Management Console, go to SIP Trunks > Add SIP Trunk, choose Generic, then VoIP Trunk Provider.
  5. Enter one DID in Main Trunk No, and configure outbound parameters with M1's SIP server IP.
  6. Add the remaining DIDs under the trunk's DIDs tab in National Number format.
  7. Create inbound rules to route calls to the correct destinations, and set outbound caller ID per extension.