U.S. Philips Corporation

Dieter A Riekmann

Ulrich R Killat

Joachim J Noll

Rolf Stecher

Franz X Meyer

In the ISDN system complex line adapting circuits are provided on the two sides of the transmission line and they handle an extensive protocol. These circuits are divided into two sub-circuits connected to one another over fixed interfaces. The sub-circuit which is located nearest to the transmission line, however, is to have a considerably varying structure depending on the transmitting medium. For a modular structure it is now proposed to subdivide this sub-circuit into two partial circuits interconnected over a newly created simple binary interface. Thus, only the partial circuit which is located nearest to the transmission line needs to be specifically designed for the transmitting medium, for example, glass fibre lines, whereas the protocol management is performed in the other partial circuit, which always has the same structure irrespective of the transmitting medium. In addition, an efficient frame structure of the newly created binary interface is devised, wherein the data supplied by the other sub-circuit are converted and also the transmission error messages are processed.

Circuit arrangement for information transmission

Method the transmission of data packets in a TDM transmission loop wherein the frame is subdivided into several groups each having the same number of words, and each group comprises either exclusively narrow-band channels for the transmission of speech data or is associated with the high-rate channel for groups comprising narrow-band channels always comprises an unambiguous bit sample of, for example, the highest priority is assigned to each group. When a subscriber station wants access to a word group in the high-rate channel it transmits its own identifying bit sample and possibly priority data in a signaling word. When this bit sample is returned through the loop undisturbed the subscriber station immediately accesses the assigned group of words in the high-rate channel for the transmission of a data packet. Allocation of channel access among individual subscriber stations is prioritized. The bit samples identifying groups comprising narrow-band channels receive the highest priority, so that these channels are automatically protected from access as a high-rate channel. A central control unit can increase the number of narrow-band channels by transmitting a further group of identifying bit samples in the signaling word.

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Pinneberg, Germany

Dieter A Riekmann