Data Bits, Control Bit And Speed - Bausch Proxima ISDN Lite Manuel D'utilisation

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Data bits, control bit and speed

The RS232 standard describes how serial information is processed (passed on). In a computer, bits are processed
concurrently (parallel). These bits are passed on one by one through the serial port. In order to make sure the receiving end
can interpret these data bits correctly, some extra bits are sent along. These are: one start bit or control bit (parity bit for error
detection) and one or two stop bits . Together they form a frame or character.
The most commonly used frame for standard asynchronous communication is 8N1:
(1 start bit + 8 data bits + 1 stop bit)
Start bit D D D D D D D D Stop bit
Data bits
Frame
Figure 13: Asynchronous Format
Apart from the frame (character), the speed (baud rate) has to be set. Speed is expressed in terms of Bits per Second (bps) or
baud.
Possible port speeds are: 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600 and 115200 bps
If data bits, control bits and speed are set at the computer end, the Proxima ISDN Lite will adapt automatically as soon as an
AT command is sent.
Attention! Check whether the computer's serial port is fit for 115200 bps.
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