U p0 interface
The U p0 interface is an interface for end devices within a private ISDN installation in telephone systems .
Functionally, it corresponds to the U K0 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, while in the public telephone network up to eight kilometers of connection line length is the rule. There are differences between the two interfaces in the way in which bits are encoded and transmitted. The advantage of the U p0 interface compared to the S 0 bus also used in private installations is the greater range. This is around two to four kilometers, depending on the quality of the line. This means that digital end devices (system telephones, but not regular ISDN telephones) can be operated even with larger internal cabling .
In contrast to the S 0 bus, digital end devices are connected via a single pair of wires . This means that existing two-core building cabling can continue to be used. The connection sockets used are usually RJ45 sockets, the wires are connected to pins 4 and 5. The transmission on this connection takes place in half-duplex mode : Both sides send alternately at twice the speed. This process is also known as ping-pong . In contrast, the U K0 interface uses the frequency equalization method .
While several terminal devices can be connected to one S 0 bus , only one terminal device can be operated on a U p0 interface without additional technical measures. However, as with the S 0 bus, the two B channels with 64 kbit / s each and one D channel with 16 kbit / s are available on this interface . Some system manufacturers offer modular, expandable telephones in which an additional telephone can be operated on the U p0 interface with a corresponding additional module . With analog modules, for example, analog terminals such as fax machines or answering machines can be connected; with S 0 modules, an S 0 bus for ISDN terminals can also be led out of the telephone with the appropriate power supply .
literature
- Dietrich Arbenz From drum voter to optiset E - The history of wired telephones for Siemens' private branch exchanges (1950–2000) , Herbert Utz Verlag, Munich 2009, ISBN 978-3-8316-0908-6 .
- Hubert Zitt: ISDN & DSL for PC and telephone. Verlag Markt + Technik, Munich 2005, ISBN 3-8272-6987-3 .
- Rudolf Nocker: Digital Communication Systems. 1. Volume, Basics of Baseband Transmission Technology, Friedrich Vieweg & Sohn Verlag, Wiesbaden 2004, ISBN 978-3-528-03976-9 .