TI545 to laptop comms problem


Thread Starter

Darin Jett

I have one TI545 plc in the plant which I normally use our old Workmaster computer (186?) to work on. I have the software installed on my laptop, it works offline fine, but when I go online, it will work for a few seconds, minutes, whatever, then hang up and timeout on communications.

Does anyone know what the serial port settings should be and the cable wiring to do this? I have a separate cable that I use which is different from the Workmaster cable, but want to verify that the pin connections are right.

Thanks, Darin Jett

Hakan Ozevin

I have no experience on TI software (TISOFT?), but if you are using Windows 98 and the software is opened in a DOS window, this may be the problem:
Since Spring 1999 some Notebook manufacturers have been using a new BIOS specification. This is a so-called ACPI BIOS (Advanced Configuration and Power Interface). If it is enabled, in dos box no COM or LPT port communication is possible.
If this is the case, start the laptop in MS-DOS mode or change the ACPI settings.

Good luck!

Hakan Ozevin

Gilles Allard

The cable pinout is documented in section 1.2 of your TISOFT manual (PPX:TS505-8101-6).
I use a different pinout; I will try to describe it

At each end, connect 1,4 and 6 together (no wire required in the cable)
At each end, connect 7 and 8 together (no wire required in the cable)
Pin 2 on PC side goes to pin 3 at the other end
Pin 3 at PC side goes to pin 2 at the other end
Pin 5 at both end are connected together

To summarize, the cable is symmetrical and only requires 3 wires and a few jumpers in the connectors.

Coming back to your communication problems, I don't think they are caused by the cable. I rather suspect that you run Tisoft over Win9X. Try running Tisoft over a real DOS (not the DOS coming with Win9X). If it works fine, then you may have a Windows configuration problem.


Darold Woodward

I have seen the same problem. It is usually worst when you are running TISOFT in a window rather than full screens. To eliminate it completely, you may need to boot to the command line and run from the command line rather than from within the Windows GUI. The problem is usually not as severe when running in full-screen mode. You can also tweak the setttings under which you run TISOFT to try to give it a more dedicated environment. When I first saw this a few years ago, it was explained as a symptom of differences in serial port interrupt handling that appeared in laptops and was made worse by running DOS apps under Windows.

Darold Woodward PE
SEL Inc.
[email protected]
I also found that on our Toshiba Satellite 4070's at work that we had to make an old style DOS config.sys for the TISOFT to run properly. We ended up with: device= ... \himem.sys dos=high buffers=40 files=40 stacks=9,256 Thanks, Gary. P.S.: Would you happen to have the pinouts for a 9-pin to 15-pin (two-row, 8 +7 pins) T.I. 405 cable?