Interfacing UCM6204 to a PA system


I’m replacing a Talkswitch 48 CVA with a UCM6204. The Talkswitch unit has an audio port (1/8" I think) which is connected to a Bogen amplifier which drives loudspeakers and creates an overhead paging system. Since the UCM6204 has no such port I’d like to be able to communicate with the amplifier via an FXS port. If I connect the FXS port directly to the amplifier I get dial tone/busy signal over the loudspeaker – not exactly what I have in mind. Has anyone done this and can therefore give me some guidance? Or, is there a gateway/ATA device that will accomplish what I’m trying to do?



first you need to understand if you need an fxs or an fxo, and then you can continue with the tests.
Do you need a signal that leaves UCM (therefore FXS) or a signal that “enters” (therefore FXO)?


You can do this using a number of SIP endpoints designed to connect old style amps/speakers to VoIP.

I usually use an Algo8180

Others here recommend a SNOM PA1


First, connecting any port from a UCM imposes one simple requirement on the other end -

When the page/call is made, something on the other end must answer before any audio will flow.

A page port on older systems simply provided the answering aspect internally so that only the audio flowed out of the system.

There are a number of ways to do this, but the key to doing it correctly is knowing what the paging device (amplifier, speakers, etc.) need from the originating point in the way of a signal.
You can look at:

Some have even resorted to taking a phone and setting it to auto answer and then using the speaker wires. A little unconventional, not very pretty, but I suppose a workable solution for the budget conscious.

There are others out there as well.


Perfect! Thanks for pointing me in the right direction. I don’t really need a SIP/VOIP solution as I was planning to use one of the FXS ports for this anyway. I found a Viking VK-FXI-1 paging adapter that I believe will work for me at a reasonable cost.


Thanks! Found a Viking VK-FXI-1 that will use FXS port, easier on the budget and I was planning to use an FXS port for this anyway. Appreciate your pointing me in the right direction.


I’d be interested to know your results. I am looking to do a similar thing replacing a TDA30 with a 3.5mm audio plug and use a UCM6208. There was an LIU that looked to be an option … but they aren’t making them anymore.


Sure, I haven’t yet ordered the adapter but I’ll post when I have results to share.


another option would be to keep the Talkswitch 48 CVA and connect the UCM to it as an analog trunk? Have a number on auto dial to the paging system (if thats possible with the Talkswitch)?



Hi Richard, there is another possibility which I have done before and it is low cost around $100 all up with the hardware.

Needs: LIU to go between an RJ11 headset port of a handset and the PA input which is a 3.5mm / 6.35mm plug and the handset itself.

A Grandstream GXP1610 is fine for that purpose - Newegg have them
An LIU to go between the handset and PA - look at the following and ask for something similar.!/LIU/p/43377101/category=11121163

The handset is programmed to be auto answer to headset port. Have the LIU plugged into the Headset Port… program the SIP details in the phone and allocate its extension as a paging group.

Adjust the volume levels to suit on the handset / liu and pa input to suit.