Search results
Results From The WOW.Com Content Network
A telephone keypad using the ITU E.161 standard. A telephone keypad is a keypad installed on a push-button telephone or similar telecommunication device for dialing a telephone number. It was standardized when the dual-tone multi-frequency signaling (DTMF) system was developed in the Bell System in the United States in the 1960s – this ...
Ringdown. In telephony, ringdown is a method of signaling an operator in which telephone ringing current is sent over the line to operate a lamp or cause the operation of a self-locking relay known as a drop. Ringdown is used in manual operation, and is distinguished from automatic signaling by dialing a number.
PBX switchboard, 1975. A telephone switchboard is a device used to connect circuits of telephones to establish telephone calls between users or other switchboards. The switchboard is an essential component of a manual telephone exchange, and is operated by switchboard operators who use electrical cords or switches to establish the connections.
You can find instant answers on our AOL Mail help page. Should you need additional assistance we have experts available around the clock at 800-730-2563.
Modern emergency telephone powered by sound alone. A sound-powered telephone is a communication device that allows users to talk to each other with the use of a handset, similar to a conventional telephone, but without the use of external power. This technology has been used since at least 1944 [ 1 ] for both routine and emergency communication ...
The 1A2 Key Telephone System is a modular system that provided flexible solutions for a variety of telephone service requirements. It provides multiple users with control over multiple telephone lines without the requirement for an operator, system attendant, or receptionist. Each user can select a specific telephone line to place calls on, or ...
A vertical service code (VSC) is a sequence of digits and the signals star (*) and pound/hash (#) dialed on a telephone keypad or rotary dial to access certain telephone service features. [1] Some vertical service codes require dialing of a telephone number after the code sequence. On a touch tone telephone, the codes are usually initiated with ...
The TeleZapper is an appliance that plugs into a consumer telephone line. On detecting a ring and answer of any phone on the line, the Telezapper will immediately play a sequence of Special information tones or "SIT": one of eight internationally standardized signals that indicate a call cannot be completed. Typically the "Intercept" or "IC ...