Apps Won't release serial Port

 I have the following problem with a PowerBook 5300c computer. The
Powerbook 5300 is hooked up to a BIOPAC Systems MP100 data acquistion
system. BIOPAC gave me software (Acknowledge 3.2) to communicate with
the MP100 data acquistion system. The I/O for the MP100 system goes thru
the PowerBook's single serial port. The MP100 needs the serial port for
data transfer and setup.
   Another system, an ATI Force/Torque gauge (F/T gauge), also needs the
serial port for setup and checkout. I am communicating with the F/T
gauge via Versaterm Pro Version 5.0.6. The reason for this is the (F/T
gauge) needs to to zeroed and set up prior to use.
   Currently I am using a manual switchbox to change between the F/T
gauge and the MP100 data acquistion system. I do the following:

    (1) Turn everything on,
    (2) Launch Versaterm Pro,
    (3) Set the manual switchbox to talk to the F/T gauge,
    (4) Send the commands to the F/T gauge with Versaterm Pro,
    (5) Quit Versaterm Pro,
    (6) Set the manual switchbox to talk to the MP100 data acquistion
    (7) Launch Acknowledge 3.2,
    (8) Collect data with the MP100 data acquistion system

   Unfortunately the F/T gauge requires constant zeroing and other
operations. So I do this:

    (1) Leave Acknowledge 3.2 active (i.e. don't quite Acknowledge 3.2),
    (2) Set the manual switchbox to talk to the F/T gauge,
    (3) Launch Versaterm Pro,
    (4) Send the commands to the F/T gauge with VersaTerm Pro.

   When I try (4) above, I get an error dialog stating that the serial
port is in use by another application. In order to proceed, I have to
quit Acknowledge 3.2. After that, I can talk to the F/T gauge.
   The Acknowledge 3.2 documentation contains nothing on how to make
Acknowledge 3.2 release the serial port.

How do I solve this prob?
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The serial port will not be released unless you quit. Think of it this way,  When you launch an app that uses the serial port, it first tries to initialise it, where would we be if our serial port connections were dropped just because an app is made inactive. Could you not use two cables, one to your printer port as a serial link to MP100 and the modem port linking to the F/T guage.
OTO356Author Commented:
The PowerBook 5300 has only one serial port. I think a Mac expert should know this.

Quitting the Acknowledge application constantly is a pain in @#$!*. That's why I have a prob. I want to release the serial port w/o quitting any apps at all.
If I ever meet a mac expert I'll pass on your advice.
maybe someday I will be able to call MYself a mac expert.
untill then...
happy answer hunting.

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Hello OTO356....
I've just had a thought, Most serial comm softwares allow you to do a disconnect or close connection, you could try this if you haven't already done so.
I hope that this works.
Quite simply - It can't be done. (unless you install another serial port!)

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I think I may have a work around that will solve your problem. Let Applescript automate your serial sessions. If you need more info on exactly how, then let me know
A possibility - try using software that emulates several serial ports on your mac.. It's a long shot...
OTO356Author Commented:
Thank you Karl. I'll look into it. I found a shareware app called CommCloser that closes serial ports. But the software author advises against closing a serial opened by application while that app is running.
OTO356Author Commented:
I found a shareware app called CommCloser that closes serial ports. But the software author advises against closing a serial opened by application while that app is running.

Any thoughts on this?
generally, applications that have their ports closed when they are meant to be open get stuck in infinite loops in attempts to re-open the driver...
CommCloser is designed for maverick apps that forget to close the ports after use..
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