what is T1 carrier in transmission
1. It multiplexes 24 voice channels over one digital channel. That is, it carries 24 voice
channels at the same time over one digital channel.
2. Each of the 24 analog inputs is sampled in round-robin fashion and its n-bit encoding
is sent down the wire.
3. Each encoding consists of 7 bits of sampled data, plus 1 bit of signaling information
(e.g., out-of-band information).
4. Each voice grade sub-channel carries (7 bits X 8000 samples) = 56kbps of data, plus
8000 bps of signaling information, requiring a digital data rate of 64kbps.
5. Samples are transmitted in 193-bit units (frames).
6. Each 193-bit frame consists of 24 8 + 1 bits of information; the extra bit of
information carries synchronization information It alternates between a ” and 1″
allowing the receiver to verify that it is properly recognizing the start and end of
frames.
7. A T1 channel has an aggregate carrying capacity of 1.544 Mbps.