I don't know much about the interacy's of analog/paging, so need some guidance. A customer has an existing PBX system with paging setup. They have to self-amplified speakers that connect to an external valcom power supply. They are putting in a new cisco solution and have an available FXO port on a voice gateway. Can they wire self-amplified speakeers directly to an FXO port and allow paging to take place accross that FXO to the speakers?(without the need for a valcom control unit)? If this is possible, would there be any problems that could arise.
thanks in advance,
I agree with you on this one (and this is actually exactly what we are doing here, with a little twist). We have non-amplified speakers here, but the premise is the same. But you need something to auto-answer the line from the FXO and then to provide power for the speakers, and the paging control unit is just the item.
We use a Valcom V-2000A single zone page control unit. This is a loop start trunk level unit, and you can purchase it for about $120 with shipping now.
The V-2000A provides 12 Valcom power units (600mA of -24VDC) for powering amplified speakers, so if you only have a couple speakers and one zone in your setup it should be more than enough for you. I think the max this thing was intended to power by itself was about a dozen speakers.
To hook it up it is just a regular RJ-11 jack out from the FXO port into the paging control unit, and then 4 wires providing signal, power and ground to the speakers. Pretty straight forward stuff. The only thing I would mention is there is a battery feed switch on the unit and like it says in the instructions make sure that it is turned on (it doesn't work very well when it's turned off, information learned from personal experience unfortunately):-).
Attached is a copy of the instruction manual for the V-2000A so you can get a look at it. Hope the info helps!
You might be able to hack something together (E&M interface would be better), but don't do it. Too easy to blow the interface without isolation components. You'll end up sending voltage into the FXO port.
Paging controllers are only a couple hundred bucks from many manufacturers. Since you have an FXO interface, you will want to look for one that does ground start and/or loop start.