RCMAC stands for recent change memory administration center , sometimes mistakenly called recent change message accounting center , in late 20th century Bell System parlance, or recent change memory administration group (RCMAG). It is an organization of people in a phone company which is responsible for programming the service and features purchased by residential and business customers into the central office . Generally the term is used only in large US phone companies called Regional Bell Operating Companies (RBOCs) .
15-526: Installing a telephone line is a complex process, involving coordinated work on outside plant and inside. Inside plant work includes running a jumper on the main distribution frame and programming the switch. Middle 20th century crossbar switches had no computer, hence the same workers who installed the jumper generally wired the necessary information into switch cross connect translations as well. Records were kept as pencil notations in ledger books or index cards. Stored program control exchanges in
30-479: A twisted pair for each local loop nearer the exchange, see outside plant . Modern implementations may include a digital loop carrier system segment or fiber optic transmission system. The local loop may terminate at a circuit switch owned by a competitive local exchange carrier and housed in a point of presence (POP), which typically is an incumbent local exchange carrier telephone exchange. A local loop supports voice and/or data communications applications in
45-437: A customer's phone service. Telephone line A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or other signaling medium connecting the user's telephone apparatus to the telecommunications network, and usually also implies
60-405: A home or other small building to a local telephone exchange . There is a central junction box for the building where the wires that go to telephone jacks throughout the building and wires that go to the exchange meet and can be connected in different configurations depending upon the subscribed telephone service. The wires between the junction box and the exchange are known as the local loop , and
75-456: A single telephone number for billing purposes reserved for that user. Telephone lines are used to deliver landline telephone service and digital subscriber line (DSL) phone cable service to the premises. Telephone overhead lines are connected to the public switched telephone network. The voltage at a subscriber's network interface is typically 48 V between the ring and tip wires, with tip near ground and ring at –48 V. In 1878,
90-497: The Bell Telephone Company began to use two-wire circuits, called the local loop , from each user's telephone to end offices which performed any necessary electrical switching to allow voice signals to be transmitted to more distant telephones. These wires were typically copper , although aluminium has also been used, and were carried in balanced pairs of open wire, separated by about 25 cm (10″) on poles above
105-558: The 1970s had teleprinter channels for entering and verifying translation information, which allowed centralizing these functions. In the 1980s, the resulting conglomeration of Teletype machines were replaced with a more organized system called MARCH which could more easily be coordinated with COSMOS , TIRKS and other operations support systems . Generally, the existence of the RCMAC organization started with 1A switches from Bell Labs (later Lucent, now known as Alcatel-Lucent), from which
120-446: The carrier access network in a traditional public telephone network, the local loop terminates in a circuit switch housed in an incumbent local exchange carrier or telephone exchange . Traditionally, the local loop was an electrical circuit in the form of a single pair of conductors from the telephone on the customer's premises to the local telephone exchange . Single-wire earth return lines had been used in some countries until
135-400: The entrances of telephone exchanges. Local loop In telephony , the local loop (also referred to as the local tail , subscriber line , or in the aggregate as the last mile ) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the common carrier or telecommunications service provider 's network. At the edge of
150-502: The ground, and later as twisted pair cables. Modern lines may run underground, and may carry analog or digital signals to the exchange, or may have a device that converts the analog signal to digital for transmission on a carrier system . Often the customer end of that wire pair is connected to a data access arrangement ; the telephone company end of that wire pair is connected to a telephone hybrid . In most cases, two copper wires ( tip and ring ) for each telephone line run from
165-416: The introduction of electric tramways from the 1900s made them unusable. Historically the first section was often an aerial open-wire line, with several conductors attached to porcelain insulators on cross-arms on "telegraph" poles. Hence party line service was often given to residential customers to minimise the number of local loops required. Usually all these circuits went into aerial or buried cables with
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#1732898045412180-414: The network of wires going to an exchange is known as the access network . The vast majority of houses in the U.S. are wired with 6-position modular jacks with four conductors ( 6P4C ) wired to the house's junction box with copper wires. Those copper wires may be connected back to two telephone overhead lines at the local telephone exchange , thus making those jacks RJ14 jacks. More often, only two of
195-520: The term "recent change memory" originated. With the introduction of various automation systems, the function of the RCMAC would recently be described as an organization of people in the phone company responsible for programming the service and features of phone service where service orders have failed to follow the automated process, investigate and resolve customer trouble reports possibly related to incorrect programming of service and features, and to support outside plant technicians repairing or installing
210-468: The walls of the house—between the house's outside junction box and the interior wall jacks —the most common telephone cable in new houses is Category 5 cable —4 pairs of 24 AWG (0.205 mm ) solid copper. Inside large buildings, and in the outdoor cables that run to the telephone company POP , many telephone lines are bundled together in a single cable using the 25-pair color code . Outside plant cables can have up to 3,600 or 3,800 pairs, used at
225-419: The wires are connected to the exchange as one telephone line, and the others are unconnected. In that case, the jacks in the house are RJ11 . Older houses often have 4-conductor telephone station cable in the walls color coded with Bell System colors: red, green, yellow, black as 2-pairs of 22 AWG (0.33 mm ) solid copper; "line 1" uses the red/green pair and "line 2" uses the yellow/black pair. Inside
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