QBASIC COM Questions

[Zylstra]

Okay,
Lets pretend that I had a COM port on my computer. Now lets pretend I have some sort of COM cable (who knows that kind exactly)
Is it possible that I could build a QBASIC program that will tell me when an electrical connection is made in a cable?
For example, if the COM cable I had an end that looked like a headphone plug with only two separate parts (wires) is it possible to make a program that will monitor the input, and tell me when something comes in through it? (If I took a piece of foil, and connected the two connections)

(A bit of a strange question)

I know that something similar can be accomplished, since my Uncle had a QBASIC program that would tell you how long it took a piece of wood to run through a saw. A start time was created, and once the log set the trigger and the time would stop.

[ValerieMay]

QBasic 4.5 will certainly do what you want but programming the ports in QB 4.5 is difficult in anything other than real Dos mode (not tried DOSBox). 

VM.

[Zylstra]

How does one start accomplishing such a program (using the OPEN COM statement)?

[ValerieMay]

Yes, that's one of the commands which are used.   Then the port must be polled while waiting for input (INP) and when that input is detected some action is taken. 

I suggest you find a tutorial which suits your purpose.  You may find a suitable one here or at one the many other QB tutorials on the WWW.  There are also dedicated QB forums.

Good luck

VM.

[ValerieMay]

A port programming tutorial written in QB is here. Download Q-Basics.zip, chapter 11 contains the tut.

If you want to try QB port programming in XP then the PortTalk driver mentioned in the above is here.

VM.