Com and printer port trouble

[Cameron]

Hello.

I have an application that uses a trigger sent from a scale to the printer
port to signify that data is ready to come from the scale to Com port 1. When
the access application recieves this data it records it and then calculates
the true weight and sends it to com port 3 which in turn is displayed on the
scale scoreboard. however, over time the application looses connection to the
printer port and stops recieving data. I'm kind of baffled by this, as this
just all of a sudden started doing this. Was there a microsoft update that
might have been responsible for my code no longer working?

 

[John Nurick]

This is outside my experience, but as no one else replied to your
previous post, here goes.

Presumably the scale uses one of the signal lines in the parallel port
to show it's ready, and presumably your Access code has to keep calling
some code that polls the port.

The first thing that comes to mind (I really am guessing here) is that
the system could be losing the connection between the LPT1: or PRN:
device that Windows makes available to the Access session and the
physical parallel port. If you connect a printer to the physical port
and open a Windows command prompt, can you send data to the printer
(remember to send a FF - Chr(12) - to make the printer output the page)?

Are there any other programs or processes that might try to access the
parallel port? If so, they could interfere with the Access application.

I suspect, however, that the solution to your problem is more likely to
be found in a Windows forum than an Access one.