Before revision: Operation Before signalling will work, the sender and receiver must agree on the signalling parameters: Full or half-duplex operation The number of bits per character
After revision: -- currently almost always 8-bit characters, but historically some transmitters have used a five-bit character code, six-bit character code, or a 7-bit ASCII.Operation Before signalling will work, the sender and receiver must agree on the signalling parameters: Full or half-duplex operation The number of bits per character