Sip trunk convert to isdn using ucm6510



I hope someone here can help me with may problem I have a POC on my client basically the goal is SIP trunk convert to ISDN using UCM6510

Kindly refer on the diagram for the reference


Why aren’t you connecting the SIP direct to the 6510?


Before a back and forth starts, with endless questions. Please, provide much more detail.

Before I went to try and make this odd setup work. Why run SIP to PRI like this?

What’s failing. What’s working? Much more details would be great.

Don’t worry if your English is poor, ( I see you’re in the Philippines), just more info please.


Hi @costwisewpg

Thank you for your response and apologize for the inadequate details. Kindly see the Attached photo updated setup

Basically, this setup was my client requirement. What I have already done in the setup was the connection of ISDN in UCM6510 and NEC PABX but upon testing

1.) Incoming call there is a prompt (The number you dial does not exist) upon checking on CDR is said No Asnwer.
2.) Outgoing Call is successful, but there is no ring from the caller side and once answered they cannot hear each other.

Note: I don’t have any issue SIP trunk configuration, it’s working. My client just wants to know if the UCM6510 can convert the sip trunk into ISDN line.

Please let me know what other details you need your help is much appreciated


No sorry, I don’t know of any mechanism to output PRI from a 6510.

I believe you’re looking for something like the Digium g1000 or g2000.


It is possible, you set the ISDN PRI on the UCM as the Master clock and the NEC would need to use its ISDN as a SLAVE - synchronising the clock from the master.

Dont forget that the UCM will have to send the NEC the DID in the format it needs or you will need to have its DID mapping changed to suit.



Hello @scottsip / kevin

Yeah UCM6510 is the master and NEC has been the slave it is connected already my issue now is the routing of a call this is the scenario of what I observe right now.

  1. (Outgoing call) Using an analog phone of NEC I dial a landline number, the call was successfully engage Caller can hear the callee, but Callee cannot hear the caller.

2.) (Incoming call) there is a prompt (The number you dial does not exist) upon checking on CDR is said No Asnwer.

Could you help me with the programming or setup for the call routing?


So what happens to the call via the logs on either the NEC or the UCM?

#9 (61.7 KB)

kindly see the PRI signalling Trace i captured right now both incoming and outgoing are working but the issue is for Incoming and outgoing call is only 1 way audio for incoming call they can’t hear us. for outgoing call also they can’t hear us.


You need to rectify the Router / Firewall issue firstly… make sure that calls are working to and through the UCM as a SIP extension before progressing to the ISDN issue.