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I'm doing a barcode project, The system is having only on single rs232 port only. I have two scanners where the data has to be sent to that one single port of the system.

A-scanner (Output) B-scanner (Output) c-system port (input)

the simultaneous data is not required here. but when the data is received from the scanner, it should sent to input of the system.

Tried in many ways.

But exhausted.

I had tried giving ATX-BRX BTX-CRX CTX-ARX.

In this only one scanner(A scanner) is able to transfer the data.

I expecting a solution for transferring data from two scanner to on single port of rs232.

Enigmativity
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mani kandan
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  • "*I expecting a solution for transferring data from two scanner to on single port of rs232.*" -- Then expect failure. RS-232 is a point-to-point connection. There are manual switches though. – sawdust Jun 29 '23 at 06:24
  • maybe you have 2 phsical and have both of those send received data to a 3rd virtual comm port. Not clear what you are doing and why. Maybe this will give you an idea https://com0com.sourceforge.net/ – kenny Jun 30 '23 at 21:51

1 Answers1

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It is possible to combine data from two RS232 devices to one physical RS232 port on the computer side.

How it works: Use a modified version of what the great Lammert Bies once described here as Half duplex RS232 spy / monitor / sniffer cable

I made a modified drawing of this, it shows an adapter cable that could be used for connecting two barcode scanners (or other RS232 DB9 devices that "just send data" and don't need any data coming from the computer side). See the drawing included. enter image description here

Limitations:

  • only one device / scanner can transmit at a time
  • only works if no handshake signal lines are required (DCD, DTR, DSR, RTS, CTS)
  • depending on the exact electric characteristics of the RS232 interfaces involved, this may or may not work reliably. In particular there can be problems if the scanners have a very weak/cost optimized RS232 transmit signal.
Oliver Heggelbacher
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  • I just saw I already described this approach several years ago... https://stackoverflow.com/questions/40258346/connect-two-serial-port-into-one-serial-port – Oliver Heggelbacher Aug 23 '23 at 10:09