Pulse dialing is a signaling technology in telecommunications in which a direct current local loop circuit is interrupted according to a defined coding system for each signal transmitted, usually a digit. This lends the method the often used name loop disconnect dialing. In the most common variant of pulse dialing, decadic dialing, each of the ten Arabic numerals are encoded in a sequence of up to ten pulses. The most common version decodes the digits 1 through 9, as one to nine pulses, respectively, and the digit 0 as ten pulses. Historically, the most common device to produce such pulse trains is the rotary dial of the telephone, lending the technology another name, rotary dialing.
Direct distance dialing (DDD) is a telecommunication service feature in North America by which a caller may, without operator assistance, call any other user outside the local calling area. Direct dialing by subscribers typically requires extra digits to be dialed as prefixes to the directory telephone number of the destination. International Direct Distance Dialing (IDDD) extends the system beyond the geographic boundaries of the North American Numbering Plan (NANP).
In electronics and telecommunications, a crossbar switch is a collection of switches arranged in a matrix configuration. A crossbar switch has multiple input and output lines that form a crossed pattern of interconnecting lines between which a connection may be established by closing a switch located at each intersection, the elements of the matrix. Originally, a crossbar switch consisted literally of crossing metal bars that provided the input and output paths. Later implementations achieved the same switching topology in solid-state electronics. The crossbar switch is one of the principal telephone exchange architectures, together with a rotary switch, memory switch, and a crossover switch.
The Strowger switch is the first commercially successful electromechanical stepping switch telephone exchange system. It was developed by the Strowger Automatic Telephone Exchange Company founded in 1891 by Almon Brown Strowger. Because of its operational characteristics, it is also known as a step-by-step (SXS) switch.
4-1-1 is a telephone number for local directory assistance in Canada and the United States. Until the early 1980s, 4-1-1 — and the related 1-1-3 number — were free to call in most states.
Call waiting is a telephone service where a subscriber can accept a second incoming telephone call by placing an in-progress call on hold—and may also switch between calls. With some providers it can be combined with additional features such as conferencing, call forwarding, and caller ID. Call waiting is intended to alleviate the need to have more than one telephone line or number for voice communications.
Bell-Northern Research (BNR) was a telecommunications research and development company established In 1971 when Bell Canada and Northern Electric combined their R&D organizations. It was jointly owned by Bell Canada and Northern Telecom. BNR was absorbed into Nortel Networks when that company changed its name from Northern Telecom in the mid-1990s.
The Pacific Bell Telephone Company is a telephone company that provides telephone service in California. The company is owned by AT&T through AT&T Teleholdings, and, though separate, is now marketed as “AT&T”. The company has been known by a number of names during which its service area has changed. The formal name of the company from the 1910s through the 1984 Bell System divestiture was The Pacific Telephone and Telegraph Company. As of 2002, the name “Pacific Bell” is no longer used in marketing, although Pacific Bell is still the holder of record for the infrastructure of cables and fiber through much of California.
A sender is a type of circuit and system module in 20th-century electromechanical telephone exchanges. It registered the telephone numbers dialed by the subscriber, and transmitted that information to another part of the exchange or another exchange for the purpose of completing a telephone call. Some American exchange designs, for example, of the No. 1 Crossbar switch used originating senders and terminating senders. The corresponding device in the British director telephone system was called a "director" and, in other contexts, "register".
A business telephone system is a telephone system typically used in business environments, encompassing the range of technology from the key telephone system (KTS) to the private branch exchange (PBX).
A Class-5 telephone switch is a telephone exchange in the public switched telephone network (PSTN) that directly serves subscribers and manages subscriber calling features. Class-5 services include basic dial-tone, calling features, and additional digital and data services to subscribers connected to a local loop.
A marker is a type of special purpose control system that was used in electromechanical telephone central office switches. Switches employing markers belong to a class of switches known as "common control", as the purpose of a marker is to control the closure of contacts in the switching fabric that connect a circuit between the calling party and the called party. This is in contrast to "direct control" switches, where the switching elements were controlled directly by the customer's dial, such as the Step by Step switch. The term marker came from its use to mark a path of links through the switching fabric. A marker's comprehensive view of the switching fabric allowed it to find and assemble a path from one terminal to another, if the links were available, unlike the earlier graded progressive systems in which a path might not be found.
Area codes 408 and 669 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of California. The numbering plan area comprises most of Santa Clara County and Northern Santa Cruz County, and includes Gilroy, Morgan Hill, Saratoga, Los Gatos, Monte Sereno, Milpitas, Sunnyvale, Santa Clara, Cupertino, Campbell, and San Jose.
A class-4, or tandem, telephone switch is a U.S. telephone company central office telephone exchange used to interconnect local exchange carrier offices for long distance communications in the public switched telephone network.
The Number One Crossbar Switching System (1XB), was the primary technology for urban telephone exchanges served by the Bell System in the mid-20th century. Its switch fabric used the electromechanical crossbar switch to implement the topology of the panel switching system of the 1920s. The first No. 1 Crossbar was installed in the PResident-2 central office at Troy Avenue in Brooklyn, New York which became operational in February 1938.
A "Community Dial Office" (CDO) was a small Class 5 telephone exchange in a rural area.
A junctor is a circuit used in analog telephone exchanges, including the Number One Crossbar Switching System, Number Five Crossbar Switching System, 1ESS switch and other switches.
A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital systems to establish telephone calls between subscribers.
The Panel Machine Switching System is a type of automatic telephone exchange for urban service that was used in the Bell System in the United States for seven decades. The first semi-mechanical types of this design were installed in 1915 in Newark, New Jersey, and the last were retired in the same city in 1983.
