The ZYCOO CooVox 4FXO Module applies to CooVox-U50/U100V1,U80,U50/U100V2 IP Phone Systems; It has 4RJ11 ports for PSTN line connection. Each port has one LED(Light-Emitting Diodes).
The LED indicates port status:
> Solid = Module loading successful
> Blink = Channel Ringing If the LED is off, the FXO module is loading failed.
All four ports on zycoo 4FXO module bracket are 6P4C RJ11 ports. The pin assignments are indentified in Tabel 1.