After the sync field, all packets are made of 8-bit bytes, transmitted least-significant bit first. The first byte is a packet identifier (PID) byte. The PID is actually 4 bits; the byte consists of the 4-bit PID followed by its bitwise complement. This redundancy helps detect errors. (Note also that a PID byte contains at most four consecutive 1 bits, and thus never needs bit-stuffing, even when combined with the final 1 bit in the sync byte. However, trailing 1 bits in the PID may require bit-stuffing within the first few bits of the payload.)
After the sync field , all packets are made of 8-bit bytes , transmitted least - significant bit first . The first byte is a packet identifier ( PID ) byte . The PID is actually 4 bits ; the byte consists of the 4-bit PID followed by its bitwise complement . This redundancy helps detect errors . ( Note also that a PID byte contains at most four consecutive 1 bits , and thus never needs bit - stuffing , even when combined with the final 1 bit in the sync byte . However , trailing 1 bits in the PID may require bit - stuffing within the first few bits of the payload . )
The first byte is what?
The first byte is what ?
a packet identifier (PID) byte
a packet identifier (PID) byte