Serial Port Bug?

Karl Larsen k5di at
Tue Nov 27 15:48:21 UTC 2007

    I have a software I like to use called gmfsk which uses the serial 
port to turn on and off the transmitter in my radio. It worked fine on 
my old computer. Now when I try to run gmfsk it puts up an error panel 
that says "Not a serial or parallel port". This made me think the new 
computer which has a serial port that is not working.

    With a volt meter I find some pins have a constant -10.7 volts on 
them which is the standard RS-232 for a no-data signal. In this static 
measure the voltmeter sees no positive volts near +12 volts.

    Wanting a way to test the serial port I recalled minicom and after 
getting it set up on /dev/ttyS0 it seems happy with Com 1. The old 
/dev/modem is gone on F7. But now what is a way to drive the serial port 
pins to a constant plus voltage with minicom?

    I have a scope that I can use if there are no way to make a constant 
positive voltage. My fear is that the serial port is broken and can't 
make a positive voltage.


	Karl F. Larsen, AKA K5DI
	Linux User

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