The Up0 interface is an interface for end devices within a private ISDN installation for telephone systems.
It is equivalent to the UK0 interface in the public network. Compared to this, it has a much shorter range, which is justified by the fact that telephone systems only have to bridge distances that occur within a building, whereas the public telephone network is up to eight kilometers long. There are differences between the two interfaces in the way in which bits are encoded and transmitted. The advantage of the Up0 interface compared to the S0 bus also used in private installations is the greater range. Depending on the quality of the cable, this is about two to four kilometers. This makes it possible to operate digital terminals (system telephones, but not regular ISDN telephones) even in the case of larger building-internal cabling.
In contrast to the S0 bus, the connection of digital terminals is made via a single dual line. Thus, an existing two-core building wiring can be used further. The used sockets are usually RJ45-doses, the wires are placed on pin 4 and 5. The transmission on this connection takes place in half-duplex mode: Both sides send alternately at twice the speed. This method is also referred to as a ping-pong method. In contrast, the UK0 interface uses the frequency matching method.
While several terminals can be connected to one S0 bus, only one terminal can be operated at an Up0 interface without additional technical measures. The two B channels with 64 kbit / s and one D channel with 16 kbit / s are nevertheless available at this interface, as with the S0 bus. Some system manufacturers offer modular extensible telephones in which an additional telephone can be operated with an appropriate additional module at the Up0 interface. Analogue modules can be connected, for example, analogue terminals such as faxes or answering machines. With S0 modules, an S0 bus for ISDN terminals can also be removed from the telephone if the power supply is adequate. Edit source text Weblinks Edit sourcetext
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