DTR Line

[stevechase]

We have a hand held PC with 2 serial ports, which can give us +5v, which we need to drive a handheld printer and a magnetic card reader. However, the state of the PIN4 on the comms connector (this is where the +5v comes out) is normally sitting at -5v, and by driving the DTR line high sets this PIN4 to +5v, and we can then drive our external equipment. The DTR line can be driven high by using the simple OPEN COM1:9600,n,8,1 line from QBasic, but if we do this we then can not monitor the status of the CTS line, which we need to do. If we open the com port using interrupts, this will enable us to monitor the CTS line, but we then can't drive the DTR line high.

So, the question is, does anyone know how to drive the DTR line high and also monitor the CTS line?

Thanks

Steve Chase
stevechase@kprmidlink.co.uk