ZYCOO 4FXO U50 U100 4 FXO module with 4 FXO interface

The Analog Trunk FXO is an interface that connects to a trunk line, like the one from your service provider. It receives ringing voltage and battery from FXS devices.  ZYCOO 4FXO U50 U100 4 FXO module with 4 FXO interface interfaces are used to connect your PBX to the PSTN. One FXO channel is required for each line you receive from your telco.

The Analog Trunk FXO provides connectivity to analog central office loop start trunk line analog interfaces. And it can be combined with BRI, PRI, GSM modules. Typically, a phone is connected to a loop start line from the Telco and is, by default, in an on-hook state. When the phone goes off-hook, the phone completes the line circuit, and the current flows through the line. The Telco provides an audible dial tone to the phone and accepts dual-tone multi-frequency (DTMF) digits from the caller.

The Central Office Interface Circuit (COIC) is the heart of the loop start Analog interface, and takes the place of a telephone when connecting to the Telco.

-Voltage detection threshold is software-selectable

The 4FXO module supports CooVox-U50/ CooVox-U100 IP  Phone System with 4RJ11 ports for PSTN line connection. Each port has
one LED(Light-Emitting Diodes).
The Red LED indicates port status:
>Solid Red= Module loading successful
>Blink Red= Channel Ringing
If the LED is off, the FXO module is loading failure

All four ports on zycoo 4FXO module bracket are 6P4C RJ11 ports. The pin assignments are identified in T abel 1.
Table 1: RJ11 Telco Port Connector