D channel protocol

D-channel protocols can realize the network termination in wide area networks or in ISDN Tk systems by means of the DSS1protocol or the 1TR6 protocol. In addition, D-channel protocols can be used to network Tk systems with each other, such as with the Q-Interface Signalling Protocol(QSIG). The ISDN D-channel protocol is structured according to the OSI reference model and defined by ITU recommendations. Control over the D channel takes place in the lower three layers. The physical layer The physical bit transmission takes place inthe physical layer (16 kbit/s or 64 kbit/s). The physical layer handles the transmission of control information in accordance with ITU-T recommendations I.430 and I.431. The most important functions of the physical layer are the generation of the bit clock, framesynchronization, echo cancellation and activation or deactivation of the terminal equipment. The bit clock determines the gross bit data rate of 192 kbit/s at the S0 interface. The frame synchronization ensures synchronization of the frames between transmitter and S0 interface. The echo channel controls the access to the D channel and the activation or deactivation is used for signaling and connection establishment or termination. The physical layer transmits the data of layers 2 and 3 in a 48-bit ISDN data frame and a gross

Englisch:	D channel protocol
Updated at:	05.11.2012
#Words:	208
Links:	channel, network, area, integrated services digital network (ISDN), digital subscriber system no. 1 (ISDN) (DSS1)
Translations:	DE
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