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rs-485 stop bit not generated.

We are transmitting data on NI RS-485/4 cards in Labwindows 5.5 under Win2000. OpenComConfig is used to configure and open the port.

When the number of STOP bits is set to 1 NO stop bits are generated.
This behaviour has been observed on a scope. The start bit is followed by data bits, followed by the parity bit. The signal then goes tri-state.

When the number of STOP bits is set to 2, 1 stop bit is observed.


When the same code is used with an RS232 port the correct stop bits are generated.

This is seen to happen on different pieces of test kit (identical configuration).
The port configuration is: 115200 Baud, 8 data bits, odd parity. Slower baud rates have been tried and the same problem is observed.


Any ideas?

Thanks
Alan
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Hello-

Please see the response in the Serial section, and use that entry from here on.

Randy Solomonson
Appplication Engineer
National Instruments
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