Folded exchange type telecommunication system
Type exchange telecommunications system is any pair of user terminal and by switching equipment under controlled conditions, to the relevant public link according to the different ways of exchange communication system, an AD hoc circuit switching mode with temporary channel; Packet switching provides a logical channel for the virtual circuit (reservation path) or datagram (random selection) of the queuing time. In front of the communication circuit switching system, calling terminal must communicate with exchange system, told the called terminal address, to exchange system to complete the addressing and succeeded after notice was called terminal, the two sides to communicate, take out stitches until the end of the communication. Packet-switched each group had a receiving terminal address and grouping serial number information, on the basis of can node in the group arrived, according to the content of the network topology database at the time, the virtual circuit and datagram respectively according to the virtual routing and minimum delay or shortest path routing, including datagram in receiving terminal only will arrive not sequential group sorting combination.
Fold broadcast point-to-point telecom system
Radio type point-to-point telecommunication system consists of a user terminal users, in a controlled or random access to a public channel (such as single frequency wireless channel or total linear, circular cable channel), and with another trusted user terminal of temporary communication system. There are two kinds of controlled access, the central system often adopts the polling method, and the non-central system is often used to pass the token. Random access is a statistical method for statistical reuse, which must be reissued after conflict. In order to reduce the probability of conflict, it is often used to send the time gap and listen to the rear hair side, and repeat the interval control.