telephony Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunications services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is ...

, mode 3 is a method of line sharing in which the line passes through a device (the mode 3 device) to connect to other devices. This enables the mode 3 device to control the line, and gain priority in need. It is a common alternative to parallel connection. For example, a

dial-up Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialing a telephone number on a conventional telepho ...

computer

modem The Democratic Movement (, ; MoDem ) is a centre to centre-right political party in France, whose main ideological trends are liberalism and Christian democracy, and that is characterised by a strong pro-Europeanist stance. MoDem was establis ...

is generally provided with two line connectors, often labelled ''line'' and ''phone''. The outside line is connected to the ''line'' connector, and handsets may be connected to the ''phone'' connector. When the modem is not in use, the line is connected to the handsets, but when the modem is in use, the ''phone'' connector is disconnected from the outside line. This prevents accidental interruption of the data service by raising the handset, which could occur if the two devices were simply connected in parallel. Other devices often wired in mode 3 include: *

Fax machine Fax (short for facsimile), sometimes called telecopying or telefax (short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer or other out ...

s. * Autodiallers including: **

Back to base The human back, also called the dorsum (: dorsa), is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck. It is the surface of the body opposite from the chest and the abdomen. The vertebral c ...

intrusion alarm A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. ...

s. **

Medical alarm A medical alarm is an alarm system designed to signal the presence of a hazard requiring urgent attention and to summon emergency medical personnel. Other terms for a medical alarm are Personal Emergency Response System (PERS) or medical alert. ...

s and similar services. In

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, mode 3 operation was facilitated by use of the 611 socket.

References

{{DEFAULTSORT:Mode 3 (Telephone) Telephony