Caller ID UCM 6202 + HT 503 + PABX Analog




I bought an ATA FXO HT 503 and it is set up next to the UCM 6202 and an analog PBX, everything is working perfectly, however I would like to set up for the VoIP SIP GXP1610 IP phone to inform you the telephone number of the connected extension HT503 only informs the SIP extension number.

Identification of calls. 5034
Caller ID required: extension number 5034 + PBX
Example: 5034 + 35 or just the number 35

Does anyone know how to do this?

Thank you for your help.

Does anyone know how to do this?

Thanks for the help.


Sorry, the question lacks some detail. You are telling us the goal of what you want, but how we need to reach the goal lacks detail of the setup.

It sounds like you have:

  1. A GXP1610 connected to a UCM.
  2. And an HT503 and it is somehow connecting the UCM to the analog PBX. Need detail of how the HT connection is made between the UCM and analog PBX and the expectation. Is the connection to the PBX treated as an incoming trunk line and where does the call go once received. Is it treated as an analog extension on the analog PBX and is so, what extension?

What is the scenario? Does the 1610 call an extension at the analog PBX. Does the 1610 transfer a call to and extension at the analog PBX? Does the 1610 transfer an external call to an extension on the analog PBX?

What is 5034?
What does 5034 + PBX mean?
What is 35?


Forgive me for the way I described.

PABX Analog Central 120 extensions.
HT503 uses analog PBX extension 257 and UCM extension 5034






Given what I understand, you would setup the FXS port of the HT503 to be a remote extension of the UCM6202 and then take the FXS analog port into your PABX as an analog trunk.

When someone from the UCM wishes to reach an extension at the PABX side, they merely dial the HT extension number whose route once at the PABX will be up to you to set within the PABX.

Conversely, when someone at the PABX side want to reach an extension on the UCM side, they will dial whatever you set that allows them to reach the HT. In other words, you may have it set so that any extension at the PABX side will dial 9 to reach the HT and then whatever extension they need at the UCM side.


And that’s right, it’s working perfectly.

Now the purpose is for the caller to work this way: when a person in the analog extension R19 calls extension 5021 of the GXP1610 device, the analog extension number appears and not the SIP number 5034 which is the HT503 number.

I’m not using the FXS port on the HT503, I’m using the FXO port.


if you mean the FXO rj port, that is for an analog PSTN line, which your diagram shows none.


I’m not using the FXS port on the HT503, I’m using the FXO port.

The FXO is in analog extension 247.
When a person dials 247 through an analog extension, the HT503 creates a communication with the SIP extension 5021.
When the Operator dials 5034, the HT503 releases the line on the analog PABX and, after dialing 19, the Operator can communicate with the person who lives in house 19


This cannot be avoided.
You connect %03 to FXS so call between 503 and R19 is internal. This analogue PBX do not give a think that you want pass number, your call IS INTERNAL for it.

For correct working you will need to USE FXO port in PABX instead of FXS.
FXS-FXS no did/dod transported.


acquire another HT503 to perform a test.

I will put this HT503 as a voip trunk because the UCM6202 identifies the phone number of the external links. Then I’ll pass the tests.

Many thanks for the feedback.


I came back to let you know that I put the HT503 ATA as a SIP trunk provider.

Now, when extension 2005 wants to talk to house 22. The operator, dial 122.
And when house 22 wants to speak with extension 5021. The house wants to speak with the operator, dial 14.

Now I can not identify which house is linking for 2005 extension.

Example: when house 22 calls extension 2005, the number 2001 appears on the display and the external number that is calling does not appear.

Can someone help me configure the caller ID for extension 5021 to see the number of who is dialing instead of the extension 2001?

follow image of CDR





I put it as FXO, but it still does not recognize calls


That’s normal i’m afraid, we need to do it more complicated (this is analogue implement limitation):

Well it could be strange but you need use both ports :slight_smile:
PBX FXO (FXS 503)- for incoming from UCM(trunk UCM - trunk PBX)
PBX FXS (FXO 503) - to dial to UCM (FXS PBX and trunk2 UCM)

Can you in taht PBX that calling some bunch of internal will be forwarded to 1 FXS line ?

This way You should have all working. FXS do not have capacity to forward CID so we need 2 settings for CID.



Looking at the topology.
the FXO is connected to an extension of the analog PBX and when the extensions dial to it it directs to the FXS the question is that the PSTN number that is dialing does not appear.

in the UCM LOG also does not tell you which PSTN number you are calling.
I believe I should check the configuration of the HT503 for caller ID it is not identifying


FXS do not transport Caller ID when calling inside, it show it own number instead.
By default FXS is end point phone which do not have possibility to set “number”. This is why CID is not transported. So we need FXO for this.

But outgoing via FXO (pbx) is same as we use FXS gateway which do not care about PBX CID as there should be phone not PBX.

That’s why we use FXO port in HT connected to FXS (pbx) so number is sent FXS get it as it internal, and FXO is obligated to sent it.

In short: incoming to PBX is via FXO and outgoing is via FXS so we can transport CID.
Only 1 problem is that will work only if set up old PBX with external number as local which point to used FXS.
If there is only 1 number external then no problem, but i think there is more.
This is for transparent calls. If you can live that from old pbx to new UCM can be terminated on IVR(UCM) where you select real destination then 2 step calls is easy to do.