FXO,FXS,E&M 1

[rawatsatish]

i would like to know the diff between FXS,FXO and E&M interfaces,and a brief detaisl about these signalling mode

 

[mbhandari]

FXS provides Ring Voltage so You can connect a phone Directally to FXS equvalent to CO.
FXO is used to connect to PBX trunk.
E&M is also used in Switch to Switch link .
You can refer to

http://www.cisco.com/warp/public/788/signalling/net_signal_control.html

 

[dddtran]

Foreign Exchange Station (FXS) provides Ring Voltage so You can connect a phone Directly to a FXS interface-pick up the phone and you should hear a dial tone.
Foreign Exchange Office (FXO) is used to a central office-the central office will suppy the ring voltage.
E&M line signaling interfaces provide two signaling leads, the E&M leads and a two- or four-wire analog input. The input for the two-wire interface comes in and out on the T1 (tip) and R1 (ring) lines; for the four-wire interface, the input comes in on the T and R lines, and goes out on the T1 and R1 lines. E&M signaling is used for tie lines between PBXs or Switch to Switch link . Hope that helps
Dave
dddtran@hotmail.com