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Sharing one RS232C port with three ham radios

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fjpompeo

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I have one PC RS232C port that needs to be shared with three ham radios to control then. According to the radios manual it cannot to be disconnected or connected in the RS232C port with PC running so is there an IC with two or three switches so I can keep the radios plugged and the switching will occurs electronically? (like CD4066 but with +-12Vcc due to RS232C need!)

Regards,

Fernando - Call sign PU2PLL - Brazil
 

banjo

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Fernando,

There is a couple of ways to do this. One way is to use a 4066 switch like you suggested. (RS-232 almost never runs at the full spec of +-12V.)

Another way is to add additional serial ports to the PC. USB to RS232 converters are fairly cheap. It would be easy to add two of these devices. As long as the total number of COM ports is less than about 6, Windows does not have a problem.

Finally, you can still find some mechanical switch boxes that would do this. While your manual states that the should not be connected or disconnected with the PC running, this is not a real requirement. The radio should be able to handle any transients from such a connection or disconnection. I have "hot-plugged" hundreds of RS232 devices through the years and never had a failure. The techs at work do it all day long.
 

artem

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fjpompeo, pay attention to how the radios are controlled - are all control pins are used ? Is there special use for RTS CTS and the rest ? I guess if your transmitter is controlled by one of those pins - that could disturb radio if only RX TX is to be switched .
 

fjpompeo

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Dear artem,

According to the manufacturers only Rx,Tx,RTS,CTS pins are needed the other control pins are not used.

Regards,

Fernando
 

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