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RS232 transmission problem

JiaJia Member Posts: 20
Our C program control a device (connecting to RS232 port) through SW RS232 driver. We have Serial Port Monitor echo everything sent by the program.

In program, string 'SSS100' is sent to device consistently, but after a period time, no more 'SSS100' shows but '?' appears during each sending period. We don't know where '?' comes from and this charactor is not surposed to be sent by RS232 port.

What the problem seems to be? HW? SW? or RS232 driver?

Jia

Comments

  • johnsonmejohnsonme Member Posts: 57
    Hi,
    It seems to be a timing problem. Try reducing the speed
    Regards,
    Johnson


    : Our C program control a device (connecting to RS232 port) through SW RS232 driver. We have Serial Port Monitor echo everything sent by the program.
    :
    : In program, string 'SSS100' is sent to device consistently, but after a period time, no more 'SSS100' shows but '?' appears during each sending period. We don't know where '?' comes from and this charactor is not surposed to be sent by RS232 port.
    :
    : What the problem seems to be? HW? SW? or RS232 driver?
    :
    : Jia
    :

  • sumitxshahsumitxshah Member Posts: 20
    Agree with Johnson,
    try to reduce the Baud rate. 9600k is the idle baud rate to get echo back.
    : Hi,
    : It seems to be a timing problem. Try reducing the speed
    : Regards,
    : Johnson
    :
    :
    : : Our C program control a device (connecting to RS232 port) through SW RS232 driver. We have Serial Port Monitor echo everything sent by the program.
    : :
    : : In program, string 'SSS100' is sent to device consistently, but after a period time, no more 'SSS100' shows but '?' appears during each sending period. We don't know where '?' comes from and this charactor is not surposed to be sent by RS232 port.
    : :
    : : What the problem seems to be? HW? SW? or RS232 driver?
    : :
    : : Jia
    : :
    :
    :

    With Regards...
    Sumit Shah.

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