A complete VLSI treatment for the LAPD protocol (ISDN level 2)

A set of ICs that can execute the bearer functions of one user network in an ISDN has been developed. This set consists of two chips for treatment of the physical layer (layer 1 of the OSI Reference Model) of the S and U interfaces, one chip for terminal adaptation and one chip for treatment of the link layer protocol carried by the D channel, the so called LAPD. The development of two of these chips is discussed. The first is the U interface layer 1 chip. The second, called TB22, is for the treatment of the signaling layer 2 function at D channel. Designed as a full custom ASIC, TB22 uses CMOS 1.25- mu m technology and has around 50000 transistors. A large demand for this device is expected.<
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