2FXO + 2FXS is mixed interface of foreign exchange office and foreign exchange station that connect to office and station. It includes 2 FXO ports and 2 FXS ports, and can be combined with BRI, PRI and GSM module. FXO interfaces are used to connect your PBX to the PSTN. One FXO channel is required for each line you receive from your telco. FXS interfaces are used on the inside of your PBX; they do not connect directly to the PSTN. One FXS channel is required for each telephone that you wish to connect to your Asterisk system.

Features:

The Analog Station Interface (FXO) provides the following features:

• Ring Generation and Ringing Trip
• Loop Closure Detection
• Loop Disconnect
• Loop Reversal
• Loop Voltage and Current Monitoring
• On-hook and Off-hook Transmission
• Hook-flash Detection
• DTMF Signalling
• Programmable Audio Gain
• On-board Power Generation
• Constant Loop Current: 20mA

The loop start Analog Interface (FXS) provides the following features:

• Detects ringing when on-hook
• Detects loop current when off-hook
• Detects tip/ring voltage crossing a set voltage when on-hook or off-hook (called DC triggering)
• Can accommodate private branch exchange (PBX) with -48V battery voltage
• Loop current range: 13~110mA
• Voltage detection threshold is software-selectable

The IPX-21SL module applies to PLANET's IPX-2100/IPX-2500, IPX-2200, and IPX-2100v2/IPX-2500v2 IP PBX System with 4 RJ11 ports for connection.