T-1 Jayhawk, a twin-engined jet aircraft used by the United States Air Force
Terrible One, BMX company
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Originally the T1 format carried 24 pulse-code modulated, time-division multiplexed speech signals each encoded in 64 kbit/s streams, leaving 8 kbit/s of framing information which facilitates the synchronization and demultiplexing at the receiver.
Since each frame of a T1 is 193 bits in length (24 channels X 8 bits per channel + 1 control bit = 193 bits), 8000 frames per second is multiplied by 193 bits to yield a transfer rate of 1.544 Mbit/s (8000 X 193 = 1544000).
Technically a DS1 is the data carried on a T1 circuit, and likewise for a DS3 and a T3, but the terms are almost always used interchangeably.
T1 Framing Patterns ------------------- To synchronize with the bit stream, the receiver picks a random bit, and then examines every 193rd bit for the presence of the special framing pattern.
The T1 Carrier standard specified in Bell Pub 62411 specifies minimum ones density in two ways (both minimums must be met) (a) an average ones density of not less than 12.5%, and (b) no more than 15 consecutive zeros between one bits.
If your T1 channel is multiplexed and demux'ed by the common carrier, B8ZS can't work until all the mux'ing equipment is upgraded to understand receiving intentional bipolar violations and regenerating them at the far end.
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