I am working on a project that has two parts, one is a ring down using FXS ports on two routers, however I need to
get the audio of what is said on the ringdown, over some PA speakers in different locations, I know you can use E&M card for audio output, however getting the audio in, it has been suggested typing the Tip & ring of the FXS port to the Tip & ring of the E&M port, is this feasable?, I would think the ring voltage would "messup" the E&M card without some kind of buffer device,

It probably will fry your E&M card.

FXS is short for Foreign Exchange Subscriber, and is used to directly ring a phone. That requires currently 100 vac 20Hz.

A E&M card is a trunk card that responds to Ear and Mouth signaling, or most usually 'wink' signalling bits starts.

If it doesn't fry, it certainly won't answer the FXS which is looking for a loop to answer.

Olden days, bell used to provide a unit called a 'ring up relay' where ring voltage would trigger a relay, and provide talk to a third device, while 48 vdc talk battery would hold up the circuit.  

The should be a paging amp out there that answers a phone.

docjohn

  thats kind of what I suspected, (usually never hurts to get a 2nd opinion) I thought if you could put something like the viking electronics M2W, between the FXS and E&M  the viking you can put regular "dial tone" in and have a low level audio output which would in turn feed the E&M card,