Display Original Caller ID when call is forwarded to external mobile phone


Hello to everyone,

I have recently installed a UCM 6202 to a customer. The system has 1 analog Trunk (FXO) and one VoIP trunk (SIP Trunk). Inbound and outbound rules work perfectly except that the customer wants
see the original caller id if the call is forwarded to his mobile phone.
The exact opposite of this topic :
# Change in Caller ID Behavior between Firmware versions and hardware
The situation is that i cannot make this to work regardless of what i did inclouding changing the Keep Original CID option in the SIP Trunk options. You see the main incoming number is the PSTN line because that is the number all his customer know but the forwarding to his mobile phone is done via the SIP Trunk because the rates to mobile phones of the SIP Trunk is much cheaper.
Can you provide some assistance??

Thank you in advance
George kaloudis


This depends on regulations re CLI in your country. Here in the UK you can only label a call with a number assigned to the line on which it’s sent. You also need to check with your provider to see if they allow you to do what you want. Many don’t allow this.
I don’t know the regulations in your country relating to this however


You need to emulate a call from the PSTN that is then sent out the SIP trunk while doing a network capture. The keep original should be on and the keep trunk should be off.

As others have mentioned. there may be limitations, either governmental or by the provider, as to what is allowed.

The capture will show if the CID is being forwarded and if so, then it is up to the provider.


Hello again

After a call to the SIP Trunk provider, I was informed that the outgoing called ID
cannot be changed unless my customer (owner of the SIP Trunk) owns that number.

Thank you all for your help

Geroge Kaloudis


For your information, this is called Clip No Screening. That allows to display the CID that we want.

Some providers do not support that.


In the Asterisk world this was and I believe still is in the SIP IP PBX - more info further…

What it was meant to do was allow carriers to send the caller id of the incoming call to the remote party - it was being abused in the past and why it has been tightened up to stop it because anyone could literally get around the caller ID being blocked and expose what number someone was ringing from.