The commonly used telephone interface types of telephone optical transceivers are: loop relay interface (FXO), analog subscriber line interface (FXS), hotline telephone interface (official telephone), magnet telephone interface.

Telephone optical transceivers are used in pairing. The telephone interface is also used in pairing. FXO and FXS must be paired, that is, FXO at one end and FXS at the other end. The hotline is used at both ends of the hotline interface, and the magnet phone is also two pairs. Both ends use the magnet telephone interface for pairing.

FXO and FXS pairing method

FXO is the loop relay interface. The FXO interface of the program-controlled exchange is used to connect to the external network, that is, the telephone line from the operator. The FXO interface of the telephone optical transceiver is often used to connect to the FXS interface of the program-controlled exchange. FXS is an analog subscriber line interface, which is used to provide a telephone interface to connect to a telephone. The central office program-controlled exchange must give the remote user a number, the central office exchange FXS connects to the telephone optical transceiver FXO, and the remote telephone optical transceiver FXS connects to the telephone; If both the office and the remote end have program-controlled switches, the central office must assign numbers to the remote end, and the remote end also assign numbers to the central office (that is, mutual assignment). According to the principle of pairing FXO and FXS, FXO vs. FXS, and FXS vs. FXO Just connect.

How to use hotline pairing
The hotline is also called the official telephone, that is, the hotline interface of the optical transceiver of the office and remote telephone is directly connected to the telephone. One end of the telephone is picked up and the other end of the telephone is automatically ringing without dialing. This method is only suitable for point-to-point communication between two telephones. It cannot communicate with the third telephone, and cannot make an outside line. It does not require a program-controlled exchange to provide a number.

How to use magnet phone pairing
Magnet phones are also called hand-cranked phones. They are dialed by shaking the phone. They are more used in military communications. The magnet telephone interfaces of the optical transceivers of the office and remote telephones are all connected to the magnet phone. One end shakes the magnet phone and the other end is a magnet phone. The machine rings automatically.