FXS(Foreign Exchange Station)simulation User Interface

can be understood as the DCE (data communications equipment) interface in Computer communication . Used to connect the terminal device with FXO ports .FXS interfaces for direct connection to the telephone; connected PBX’s outside line, with FXS interface to provides feed signal to the PBX trunk outside line . as shown below:

FXO(Foreign Exchange Office) Analog trunk interface

can be understood as the DTE (Data Terminal Equipment) interface in Computer communication. Connecting with telephone switching equipment with FXS ports, FXO interfaces for connecting PSTN, for connecting with PBX extension inside side, PBX provide a feeding signal to FXO interface.

FXS and FXO Looped opening and closing through two-core cable with the current signal to complete the telephone call control.

NOTE: 

Simple to understand. FXS: can be connected with telephone set and PBX outside port. FXO: can connect the company's internal PBX extension port and the telecom operator’s direct line. 

More prosaically ,FXO is a telephone set, so it just only lead out an line from company's internal PBX or apply an direct line from Telecommunications operator, and connect directly with FXO port. 

E1 is a digital interface, 30-channels telephone(voice) are user more in China and Europe .T1 .T1 is American standard ,T1 is 24-channels telephone(voice)!

TAK's Related Products: 

E1 PCM multiplexer 

voice over fibre multiplexer

 one of the picture of E1 PCM multiplexer:

one of the picture of voice over fibre multiplexer: