Couple of weeks ago I put in a 3CX onsite with 63 GS handsets. The client had a 20 channel E1 circuit and we needed a temporary gateway to interface the E1 to 3CX. Normally I’d use a Beronet E1 gateway but I couldn’t find one at any of the UK distributors. In the end I bought a UCM6510 from my GS supplier and used it as a gateway and thought it may help someone else who wanted to try. Incidentally the UCM6510 as a gateway was the least expensive option.
Set up a peer SIP trunk to the 3CX server. The important point here is the check the ‘Keep Original CID’ box on the trunk
An inbound route on the E1 trunk. It’s important here to select ‘ByDID’ as the default destination, check the ‘Dial Trunk’ box and I set ‘Extension’ in the ‘Allowed DID Destination’ edit box.
An outbound route to match the above to send calls to the 3CX server.
Next an inbound rule on the trunk from the 3CX server selecting ‘ByDID’ as the default destination, check the ‘Dial Trunk’ box and I set ‘Extension’ in the ‘Allowed DID Destination’ edit box.
Lastly an outbound route to send calls from the SIP trunk out on the E1 circuit.
One point to note here is that the permissions on each rule have to match. I used ‘International’ throughout.
Worked well, went in first time and from my point of view was a much better option that a gateway. Calls pass from the E1 to 3CX and 3CX to E1 preserving DDI and CLI both ways with little or no latency
Hopefully it will help someone in the future