Forwarding a call to another extension doesnt show caller number


Here is the issue we have lately.
Seems like accidentaly we created the following “rule”: When someone calls and there is need of forwarding this call to another extension, then the forwarded number isnt shown.
Instead, it is shown the extension that forwarded the call.

Example (due to make it clearer, since english is not my native language.

External call by 001.12345679 calls.
The extension 201 receives the call.
Then extension 201 wants to forward the call to extension 202.
202 receives the call, but instead of seeing 001.12345679, it sees 201.

Could someone advice how to solve this? It was working perfectly for years, but seems like we accidentally broke it.

Thanks in advance!

How are you forwarding? If you are doing a native SIP attended transfer, this is exactly what will happen, at first, as Asterisk will have no way of telling that you are forwarding a call, rather than making an enquiry on a second line.

Hello David,

unfortunately I have no idea what you mean with: a native SIP attended transfer".
For years, it was working as expected, meaning it was showing the caller tel.number. Seems like we accidentally modified it, and now it shows the internal id that makes the transfer.

Probably the correct word is “transfering a call”, not “forwarding a call”.
Does this makes sense to you?

Native SIP attended transfer.

Phone B receiving call from A.

B sends INVITE C to PABX.

PABX sets up call to C and returns 200 OK to B

B sends REFER with Replaces to PABX.

PABX sends accepted

PABX sends NOTIFY 200 OK.

Native half attended SIP transfer:

REFER sent before C answers.

NOTIFY’s for intermediate statutus.

Native SIP Blind Transfer:

B sends REFER without Replaces and without inviting C.

Blind Transfer simulated with native Attended Transfer:

On pressing blind transfer, phone does INVITE to C then, immediately,REFER with replaces and follows through as for half attended.

Non native transfers

B sends Asterisk feature code to PABX.