Channels of phones or phones (or just lines or circuits in industry) are single user circuits in telephone communication systems. It is a physical cable or other signaling medium that connects the user's telephone apparatus to the telecommunications network, and usually also implies a phone number for billing purposes provided to that user. Telephone lines are used to transmit landline telephone and cable phone service Digital subscriber line (DSL) to the location. Phone line connected to public switched telephone network.
Video Telephone line
United States
In 1878, the Telephone Company Bell began using a two-wire circuit (called a local loop) from each of the user's phones to the end office that made the necessary electrical switch to allow the voice signal to be transmitted to a further phone.
These cables are usually copper, although aluminum has also been used, and carried in a balanced open wire pair, separated about 25 cm (10 ") on the pole above the ground, and then as a twisted pair cable. Modern lines can run underground , and may carry analog or digital signals to the exchange, or may have a device that converts analog to digital signals for transmission on the operator system.
Often end customers from the wire pair are connected to the data access settings; the phone company's end of the wire pair is connected to the hybrid of the phone.
In many cases, two copper cables (ends and rings) for each telephone line run from home or other small buildings to a local telephone exchange. There is a central connection box for the building where the cable goes to the phone jack throughout the building and the cables that go to the exchange place meet and can be connected in different configurations depending on the subscription phone service. The cables between the junction box and the exchange are known as local loops, and the wired network goes to the exchange, access network.
Most homes in the US are fitted with a 6-position modular jack with four conductors (6P4C) connected to a home connection box with copper wires. The cables may be reconnected to two telephone lines at the local telephone exchange, thus making the jack jack the RJ14. More often, only two of the cables are connected to the exchange as one phone line, and the other is not connected. In this case, the jack at home is RJ11.
Older homes often have telephone cable 4-conductor on the wall colored Bell System: red, green, yellow, black as 2-pairs of pure copper 22 AWG (0.33Ã, mmÃ,²); "line 1" uses red/green pair and "line 2" using yellow/black pair. Inside the walls of the house - between the box outside the intersection house and interior wall jack - the most common telephone cord in the new houses is Category 5 cable - 4 pairs of pure copper 24 AWG (0.205 mmÃ,²).
In large buildings, and in the outdoor cables leading to the POP telephone company, many telephone lines are combined in one cable using 25-pair color codes.
Maps Telephone line
References
Source of the article : Wikipedia
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