| Calls Per Line: | 1 |
| Requirements | POTS to SIP conversion device |
Plain old telephone service (POTS) is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in most parts of the world. The name is a retronym, and is a reflection of the telephone service still available after the advent of more advanced forms of telephony such as ISDN, mobile phones and VoIP.
POTS has been available almost since the introduction of the public telephone system in the late 19th century, in a form mostly unchanged to the normal user despite the introduction of Touch-Tone dialing, electronic telephone exchanges and fiber-optic communication into the public switched telephone network (PSTN).
The system was originally known as the Post Office Telephone Service or Post Office Telephone System in many countries. The term was dropped as telephone services were removed from the control of national post offices.
POTS services include:
* bi-directional, or full duplex, voice path with limited frequency range of 300 to 3400 Hz: in other words, a signal to carry the sound of the human voice both ways at once;
* call-progress tones, such as dial tone and ringing signal;
* subscriber dialing;
* operator services, such as directory assistance, long distance, and conference calling assistance;
* a standards compliant analog telephone interface including BORSCHT functions
In the United States, the pair of wires from the central switch office to a subscriber’s home is called a subscriber loop. It is typically powered by
