A 16×16 crosspoint switch for ternary encoded signals

A crosspoint-switching chip that can switch bipolar, alternate mark inversion encoded (AMI) signals directly, is described. AMI encoding is a form of ternary, return-to-zero (RZ) coding where a binary zero is represented by an absence of a pulse and ones are represented with an alternating sequence of positive and negative pulses. Bipolar signals are used widely in interoffice telecommunications such as the T1, T1C, T2, and T3 digital transmission systems. The switching chip has 16 input and 16 output channels. Control of the chip allows any input to be connected to any output or outputs, providing a nonblocking connection. The architecture allows for expansion of the crosspoint array by paralleling several chips. The chip, fabricated using a standard 3-μm CMOS technology, is capable of handling data rates up to 15 Mb/s per channel, has about 17000 transistors, and has an area of about 32.5 mm²