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5XB Switch
The Number Five Crossbar Switching System (5XB switch) is a telephone switch for telephone exchanges designed by Bell Labs and manufactured by Western Electric starting in 1947. It was used in the Bell System principally as a Class 5 telephone switch in the public switched telephone network (PSTN) until the early 1990s, when it was replaced with electronic switching systems. Variants were used as combined Class 4 and Class 5 systems in rural areas, and as a Telegraphy#Telex, TWX switch. 5XB was originally intended to bring the benefits of crossbar switching to towns and small cities with only a few thousand telephone lines. The typical starting size was 3000 to 5000 lines, but the system had essentially unlimited growth capacity. The earlier 1XB switch, 1XB urban crossbar was impractically expensive in small installations, and had difficulties handling large trunk groups. 5XB was converted to wire spring relays in the 1950s and otherwise upgraded in the 1960s to serve exchanges wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Exchange
A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises. It facilitates the establishment of communication circuits, enabling telephone calls between subscribers. The term "central office" can also refer to a central location for fiber optic equipment for a fiber internet provider. In historical perspective, telecommunication terminology has evolved with time. The term ''telephone exchange'' is often used synonymously with ''central office'', a Bell System term. A central office is defined as the telephone switch controlling connections for one or more central office prefixes. However, it also often denotes the building used to house the inside plant equipment for multiple telephone exchange areas. In North America, the term ''wire center'' may be used to denote a central office location, indicating a facility that provides a telephone with a dial tone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-frequency
In telephony, multi-frequency signaling (MF) is a type of signaling that was introduced by the Bell System after World War II. It uses a combination of audible tones for address ( telephone number) transport and supervision signaling on trunk lines between central offices. The signaling is sent '' in-band'' over the same channel as the bearer channel used for voice traffic. Multi-frequency signaling defines electronic signals that consist of a combination of two audible frequencies, usually selected from a set of six frequencies. Over several decades, various types of MF signaling were developed, including national and international varieties. The CCITT standardization process specified the American Bell System version as ''Regional Standard No. 1'', or Signalling System R1, and a corresponding European standard as Signalling System R2. Both were largely replaced by digital systems, such as Signalling System 7, which operate out-of-band on a separate data network. Because o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panel Switch
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. The Panel switch was named for its tall panels which consisted of layered strips of terminals. Between each strip was placed an insulating layer, which kept each metal strip electrically isolated from the ones above and below. These terminals were arranged in ''banks'', five of which occupied an average selector frame. Each bank contained 100 sets of terminals, for a total of 500 sets of terminals per frame. At the bottom, the frame had two electric motors to drive sixty selectors up and down by electromagnetically controlled clutches. As calls were completed through the system, selectors moved vertically over the sets of terminals until they reached the desired location, at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Register Signaling
In telecommunications, register signaling provides addressing information, such as the calling and/or called telephone number A telephone number is the address of a Telecommunications, telecommunication endpoint, such as a telephone, in a telephone network, such as the public switched telephone network (PSTN). A telephone number typically consists of a Number, sequ .... R2 register signaling is an example. This is contrasted with line signaling. References Telephony signals {{telephony-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class 4 Telephone Switch
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. A class-4 switch does not connect directly to telephones; instead, it connects to other class-4 switches and to class-5 telephone switches. The telephones of service subscribers are wired to class-5 switches. When a call is placed to a telephone that is not on the same class-5 switch as the originating subscriber, the call may be routed through one or more class-4 switches to reach its destination. Etymology ''Tandem'' derives from the Latin adverb ''tandem'' meaning ''at length'', and is used in English to mean a group of two people or machines working together, usually in series. A tandem switch is used to interconnect other switches via trunks. Thus, tandem switches are always part of a series of switches and lines that connect telephone callers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cord Circuit
In telecommunications, a cord circuit is a switchboard circuit in which a plug-terminated cord is used to establish connections manually between user lines or between trunks and user lines. A number of cord circuits are furnished as part of the switchboard position equipment. The cords may be referred to as front cord and rear cord or trunk cord and station cord. In modern cordless switchboards, the cord-circuit function is switch operated and may be programmable. In early and middle 20th century telephone exchange A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises. It facilitates the establishment of communication circuits ...s this task was done by a supervisory relay set known variously as junctor circuit or district junctor. Later designs made it a function of the trunk circuit or absorbed it into software. See also * Switched loop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coin Phone
A payphone (alternative spelling: pay phone or pay telephone or public phone) is typically a coin-operated public telephone, often located in a telephone booth or in high-traffic public areas. Prepayment is required by inserting coins or telephone tokens, swiping a credit or debit card, or using a telephone card. The company that operates the payphone generally pays either rent or a revenue share to the owner of the property where the phone is installed. Invented in the late 19th century, payphones became ubiquitous worldwide in the 20th, enough to contribute to the notion of universal access to basic communication services. The charge for a call may be a flat rate, or dependent on call duration. Following the explosive growth of mobile telephony, the use of payphones, and the number installed, has decreased greatly. Countries Canada Most payphones in Canada are owned and operated by large telecom providers such as Bell, Telus Communications, and SaskTel. In the last 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E And M Signaling
E and M signaling is a type of supervisory line signaling that uses DC signals on separate leads, called the "E" lead and "M" lead, traditionally used in the telecommunications industry between telephone switches. Various mnemonic names have been used to memorize these letters, such as ''Earth'' and ''Magneto'' or ''Ear'' and ''Mouth'', the most common variation. E&M was originally developed for signaling between PABXs in different geographic locations over an analog private circuit. The protocol was later extended for use on digital carrier system with Channel Associated Signaling (CAS). Signaling units and trunk circuits The E&M standards were initially developed by Bell Labs and extended by national PTT administrations. The standard defines two sides of the interface, the trunk circuit and the signaling unit. The trunk circuit is normally the side to which the PABX is connected. The signaling unit is the special modem that converts the DC signaling protocol into tones th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TSPS
The Traffic Service Position System (TSPS) was developed by Bell Labs in Columbus, Ohio to replace traditional cord switchboards. The first TSPS was deployed in Morristown, New Jersey in 1969 and used the Stored Program Control-1A CPU, "Piggyback" twistor memory (a proprietary technology developed by Bell Labs similar to core memory) and Insulated Gate Field Effect Transistor solid state memory devices similar to dynamic random access memory. Features The TSPS system utilized special analog trunks that originated at Class 5 end office circuit switch systems and Class 4 toll access circuit switch systems that were connected to Class 3 primary toll circuit switch systems such as the 4A-ETS/PBC and 4ESS switch systems. The TSPS system did not perform switching between the originating end office switch and the toll switch for the subscriber voice path. The TSPS system included the "Remote Trunking Arrangement" (RTA) feature that consolidated the trunk connection at the origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Message Accounting
Automatic message accounting (AMA) provides detailed accounting for telephone calls. When direct distance dialing (DDD) was introduced in the US, message registers no longer sufficed for dialed telephone calls. The need to record the time and phone number of each long-distance call was met by electromechanical data processing equipment. Centralized AMA In centralized AMA (CAMA), the originating Class 5 telephone switches used automatic number identification (ANI) and multi-frequency (MF) signaling to send the originating and dialed telephone numbers to the Class 4 toll connecting office. The Class 4 office recorded this information with punched tape machines on long strips of paper, that had approximately the width of a hand. Each day a technician cut the paper tapes and sent them to the accounting center to be read and processed to generate customer telephone bills. Each punch recorder was responsible for 100 trunks, and its associated call identity indexer (CII) identified th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
