Synchronous And Asynchronous Communication; Figure D-1: Asynchronous Data Format Examples - PictureTel Concorde 4500 Servicing Manual

CONTROL AND DATA PORT COMMUNICATIONS
F Y I
Synchronous
and
Asynchronous
Communication
D-2
7 Data bits with no parity
1
S
7 Data bits with parity
1 2
S
8 Data bits with no parity
1 2
S
8 Data bits with parity
1 2
S

Figure D-1: Asynchronous Data Format Examples

The Concorde¥4500 handles 7 data bits with parity the same
F.Y.I.
way it handles 8 bits with no parity because the parity bit is
passed through an eighth bit.
Synchronous communication, also referred to as bit-synchronous
communication, uses a clock signal to regulate data transfer. The
clock signal is a square wave with a regular period or cycle that
matches the baud rate. Because the sender transmits one bit with
each cycle of the clock signal, this method of data transfer is called
synchronous communication.
2 3 4 5 6 7
3 4 5 6 7
3 4 5 6 7
3 4 5 6 7
Stop bits
P
Stop bits
8
Stop bits
8 P
Stop bits