FXS-FXO VOIP You May Also Be Interested In: copper cables fxo voip fxs and fxo fxs fxo fxs fxo voip
The question What is the difference betweenFXS and FXO? is frequently asked by those deploying Patton Voice-over-InternetProtocol (VoIP) Smart Node solutions. Foreign exchange Subscriber (FXS) andForeign exchange Office (FXO) are the names of the two most common interfaces(ports or plugs) found in analog telephony environments. Analog telephony, alsoknown as Plain Old Telephone Service (POTS) , is the service the local phonecompany typically delivers to your home. Local phone companies deliver POTSfrom their Central Office (CO) to the subscribers premises over a circuitconsisting of two copper wires. To increase the distance over which the signalcan be transmitted the two wires are twisted together, which also reduceselectromagnetic interference. So these two-wire copper cables are commonlyknown as twisted pairs.


FXS - Foreign exchange Subscriber interface(the plug on the wall) delivers POTS service from the local phone companysCentral Office (CO) and must be connected to subscriber equipment (telephones, modems, and fax machines) . In other words an FXS interface points to thesubscriber. An FXS interface provides the following primary services to asubscriber device:
Dial Tone

Battery Current

Ring Voltage

FXO - Foreign exchange Office interface (theplug on the phone) receives POTS service, typically from a Central Office ofthe Public Switched Telephone Network (PSTN) . In other words an FXO interfacepoints to the Telco office. An FXO interface provides the following primaryservice to the Telco network device: