Hangzhou TAK Communication Co.,ltd shows how to simply test for the phone(FXS/FXO) of the PCM multiplexer on the production site. 

It is just an simple way to see if the phone can call and answer. Firstly power on,and connect with E1 line cable with two side(FXS side and FXO side PCM multiplexer), then each PCM multiplexer connect with the phone set, and call each other, and answer to see if both side FXS and FXO is ok for telephone using.

 For more information,please view our youtube link:  https://youtu.be/3LXelwHSKKo