What does FXS stand for?

In the realm of analog telephony, two primary interfaces, known as Foreign eXchange Subscriber (FXS) and Foreign eXchange Office (FXO), play a pivotal role.

These interfaces, commonly referred to as ports or plugs, are the fundamental connectors in traditional phone systems.

The FXS interface is designed to connect directly to a standard telephone handset, providing the necessary signals and power to operate.

On the other hand, the FXO interface functions as the point of connection between the telephone line and the telephone equipment, such as a PBX or key system.

Analog telephony, often referred to as Plain Old Telephone Service (POTS), is the traditional service offered by local phone companies to residences.