Integrating SIP with Simplex 5100 PA System


We are looking into integrating an old Simplex 5100 PA with our Current FreePBX system, I know this is not 100% FreePBX related but I figured I would consult some more experienced people here :slight_smile:

So Our 5100 PA uses and admin station phone that you can Dial #10 in order to do an All-Page. Do any of you know the best way I could tie this into a SIP phone? It uses a proprietary amp so integrating directly with the amp with a SIP paging adapter is a no go for now.
I didn’t know if I could configure an ATA to auto answer the call and then send a DTMF tone over to initiate the page better yet if that’s possible is there way to confine that all to one button on a SIP phone. Almost like script the call? If that’s a thing.

We are looking to RIP this entire system out in the future however the speakers use a nonstandard voltage so that bumped it out of the budget range for now. So I am just looking for the best method to accomplish this.


Once you can get the PA system responding to an ATA, such that the PA auto-answers calls to the ATA, then it should be a simple matter to create a short custom dialplan to send the DTMF after answer to initiate the page.

I will Run back over and verify this but if I remember right when the phone plugged into the 5100 Goes off hook the PA sends a dial tone. Would this interfere with the ATA at all? Almost like the PA side is the FXS and the ATA would need to be the FXO?

You could also look at using a sip paging adapter such as one from Snom or Cyberdata

Only problem with that is I have no idea how to integrate one of those into the panel. It seems like all of the functions like swapping inputs and whatnot require the admin phone to dial a string to initiate it. There are no buttons on the panel itself.

Get an ATA with 1 FXO port e.g. Obihai, Grandstream or Linksys. Set it up as a trunk. Create an Outbound Route that maps your desired page code to #10. No need for any custom dial plan; the ATA will generate the DTMF automatically.

Thanks Stewart, That makes sense in my head but I am slightly confused how the ATA will generate the DTMF automatically.
PA will plug into the FXO port and when you make a call that matches the outbound route the ATA should just pass it though to the PA but how would the #10 get added in there? would that just be an “append” to the route?

Set prefix to what the user dials, prepend to #10 and leave match pattern blank. What the user dials is removed and #10 is added, so #10 is sent to the ATA, which sends it out as DTMF.

Oh that makes sense… Ordered a Grandstream HT813, I 'll let you know how it goes!

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