Baud Rate; Figure D-2: Synchronous And Asynchronous Data Patterns - PictureTel Concorde 4500 Servicing Manual

Synchronous data
Transmit clock
Transmit data
Asynchronous data
Transmit data

Baud Rate

Asynchronous communication uses start bits and stop bits to regulate
data transfer. The sender precedes each word of data with a start bit
and ends each word with one or more stop bits.
When the receiver senses the arrival of start bits, it can identify the
real data that follows immediately after the start bits. The receiver
strips off the start and stop bits and moves the real data to its
destination. Because this data is not sent according to any regular
interval, this method of data transfer is called asynchronous
communication.
The following Þgure shows typical synchronous and asynchronous
data patterns.
1 2
1 2
Start bit
Figure D-2: Synchronous and Asynchronous
The baud rate generally refers to the speed at which a unit of
information moves from one device to another. If the unit of
information is equal to one bit, then bit rate and baud rate are
equivalent (measured in bits per second or bps). Most asynchronous
3 4 5 6 7
3 4 5 6 7
Data Patterns
Baud Rate
8
9
Parity and or
stop bits
D-3