Serial com port trouble

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Hi too all,

I have a problem with a comm port. The board is a SOYO K7VMP2. I plan
to use it with a ham radio transceiver to put it in TX mode via a
software. The signal is sent trough a DB25 (RTS with pn 5 and 7).

 Here what is happening:

The PC is off, I plug on the serial port the cable from the radio, and
nothing happen, even if the radio is on. The radio works as it should
in receive mode.

But as soon as I start the PC, the radio switch to tx.. and stay that
way while and after WinXP loads.

...I repeat as soon as I start before the Bios sequence begin.

Any help would be welcome

Pierre VE2PID

Re: Serial com port trouble

Sounds like you're using the wrong signal. Pin 5 is "clear
to send".
You should be using pin 4 "request to send"? Anyway look at
information sources about the serial port.

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Re: Serial com port trouble

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Sounds like the 9 and 25 pin connectors are mixed up, so you may find the
wires crossed.

9 pin:

pin 5 ground
pin 7 RTS

25 pin:

pin 5 CTS
pin 7 ground

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