COM port problem
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Hi I need send and receive information from "single COM port" to "2 COM port", We know COM has 9 pin and with only 3 pin you can send & receive into one device. So physically this is possible. and I want to know how can implement with C#.
Best Regards, Reza Shojaee
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Hi I need send and receive information from "single COM port" to "2 COM port", We know COM has 9 pin and with only 3 pin you can send & receive into one device. So physically this is possible. and I want to know how can implement with C#.
Best Regards, Reza Shojaee
How to use COM port in C#[^] Sorry - didn't understand your question properly. My bad.
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modified on Saturday, October 31, 2009 7:44 AM
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Hi I need send and receive information from "single COM port" to "2 COM port", We know COM has 9 pin and with only 3 pin you can send & receive into one device. So physically this is possible. and I want to know how can implement with C#.
Best Regards, Reza Shojaee
I don't know how to split COM port, but I don't think it's possible. The only way is using RS485 Modbus, the interface is like RS232, in RS485 you can send your data to all clients just with device address in the first in your byte array. That means your clients must have a number, for example client1 and client2. You can use SerialPort class also.
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Hi I need send and receive information from "single COM port" to "2 COM port", We know COM has 9 pin and with only 3 pin you can send & receive into one device. So physically this is possible. and I want to know how can implement with C#.
Best Regards, Reza Shojaee
Having read the Stancrm post, I see what you are trying to do. If you connect two external machines to a single RS232 port, it may work. RS232 is intended for point to point work, not multidrop and its electrical specification is designed for just that. Certainly, the two devices will be able to hear anything you transmit on the port, (at least until the distances from the source port get too big) but it is unlikely that transmissions into the port from one of two connected devices will work - it may, but it will depend on the design of the hardware connected to the port and the physical tollerances of the components. (i.e. it may work with these two devices, but if one of them is changed for an identical model it may not, or it may work but only intermittently). I would really consider why you are doing this, and look at better technology for it, such as RS485 or USB.
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Having read the Stancrm post, I see what you are trying to do. If you connect two external machines to a single RS232 port, it may work. RS232 is intended for point to point work, not multidrop and its electrical specification is designed for just that. Certainly, the two devices will be able to hear anything you transmit on the port, (at least until the distances from the source port get too big) but it is unlikely that transmissions into the port from one of two connected devices will work - it may, but it will depend on the design of the hardware connected to the port and the physical tollerances of the components. (i.e. it may work with these two devices, but if one of them is changed for an identical model it may not, or it may work but only intermittently). I would really consider why you are doing this, and look at better technology for it, such as RS485 or USB.
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About possibility or no, I saw this configuration physically & with delphi software. About using USB or RS485, My devices work with RS232.
Best Regards, Reza Shojaee
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About possibility or no, I saw this configuration physically & with delphi software. About using USB or RS485, My devices work with RS232.
Best Regards, Reza Shojaee
You can buy RS232 - RS485 converters from about £5 - don't know how good they are. Similarly RS232 - USB converters, but they are more expensive. Either solution would work better and be more reliable than multidrop RS232.
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Hi I need send and receive information from "single COM port" to "2 COM port", We know COM has 9 pin and with only 3 pin you can send & receive into one device. So physically this is possible. and I want to know how can implement with C#.
Best Regards, Reza Shojaee
You'll need hardware that can allow to use pre-defined pin(s) as RX/TX. For most standard uart hardware cards, the UART COM is usings pins #2/#3 (for RS-232). The other pins are used for RS-422/485 & handshake (RTS/CTS etc.) purpose. If you have any FPGA & VHDL knowledge, you could code yourself some generic UART module that can handle 2 rs-232 on different pins assignments. and then use it as "middle-box" to communicate via it. Could be some1 made such product already...
