DS1C
<communications> A DS level and framing specification for digital signals
in the North American digital transmission hierarchy. A DS1C signal uses 48 PCM
channels and has a transmission rate of 3.15 Megabits per second, twice that of
DS1.
DS1C uses two DS1 signals combined and sent on a 3.152 megabit per second
carrier which allows 64 kilobits per second for synchronisation and framing
using "pulse stuffing". The channel 2 signal is logically inverted, and a
framing bit is stuffed in two out of three code words, resulting in 26-bit
information units. The channels are interleaved and then scrambled by the
addition modulo 2 of the signal with the previous bit. Finally the bit stream is
combined with a control bit sequence that permits the demultiplexor to function
by preceding each 52 bits with one DS1C framing bit. A series of 24 such 53-bit
frames forms a 1272-bit "M-frame".
(1995-02-07)
Nearby terms:
dry run « DS0 « DS1 « DS1C » DS2 » DS3 » DSA
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