Nearly every business is switching to voip phone system now. FXS and FXO are two types of interfaces commonly used in traditional analog phone systems. What are the differences?
FXS vs FXO
FXS—Foreign eXchange Subscriber interface is a plug on the wall that delivers POTS service/the analog line and supplies battery power, provides dial tone and generates ringing voltage.
FXO—Foreign eXchange Office interface is a plug on the phone that receives POTS service/the analog line and generates off-hook and on-hook indications(loop closure).
FXS/FXO without a PBX
FXS/FXO with a PBX
FXS Gateway and FXO Gateway
An FXS (Foreign Exchange Station) gateway is a device that connects analog devices such as telephones, fax machines, and modems to a VoIP network. The FXS gateway provides power to the device and establishes the communication link with the VoIP network. It converts the analog signals from the device into digital signals that can be transmitted over the internet. In other words, an FXS gateway acts like a telephone company's central office.
An FXO (Foreign Exchange Office) gateway is a device that connects a VoIP network to the PSTN (Public Switched Telephone Network) and allows users to make calls from their VoIP phones to the traditional PSTN network. An FXO gateway receives incoming analog signals from the PSTN and converts them into digital signals that can be transmitted over the internet. In other words, an FXO gateway acts like a telephone company's local exchange.
Use Cases of FXS Gateway and FXO Gateway
Connect Analog Devices to VoIP Phone System
Businesses who want to retain their analog devices like analog phones, fax machines, modems and other POTs like door access, fire alarms by simply connect them to FXS gateways, and enjoy the convenience and cost savings of future-proof SIP-based enterprise phone systems or unified communications. FXO gateway connects the VoIP phone system to the PSTN lines.
Legacy PBX to SIP/VoIP Network
An FXS gateway also can be used to integrate legacy PBX with a modern VoIP network. This enables businesses to modernize their systems without replacing all their legacy equipment.
PSTN Fallback
An FXO gateway can be used by PSTN fallback for businesses, to connect their VoIP phone systems to the PSTN. This ensures that they can still make and receive calls in the event of an internet failure and VoIP system go down.
