Dios del Universo

Troubleshooting the Serial Port Connection

About 20% of the time (based on my experience), serial port based software (LT1_Edit, TTS Datamaster, Tunercat’s Flash Programming Utilities) doesn’t work the first time it’s loaded on a computer. 99.9% of the time, it’s the computer’s fault. ;) We’ll talk about the other .1% later, but the primary goal of this document is to help you troubleshootyour laptop and figure out why things aren’t working like they should. Read through this document completely to get some ideas, and then go back and walk through some steps. I can get pretty random with my instructions, maybe you’ll see something that helps.

OK, so you’ve loaded up the software, you have the cable hooked to the laptop, the other end of the cable hooked to the vehicle, the vehicleignition switch is in the “On” position, you’ve configured the software to use the port on the back of the computer, and you can’t “connect” to the vehicle. That’s our general problem.

The first thing to check is our COM ports under Windows95/98 (I’m assuming these operating systems).

Follow this progression with mouse clicks…

Start…

Settings…

Control Panel…

Double click on the“System” Icon…

Click on the “Device Manager” Tab…

Now look down the list, scrolling down if you have to, and find the section labeled “Ports (COM & LPT)”. You should see a window that looks like this:


First off, do you see “Communications Port (COM1)” in the list on your computer? Do you see any COM ports on your computer? If you don’t see any COM ports, then you may need to go in to yourBIOS and enable them. Just before your computer boots, you hit something like or - or hold down the F1 key while turning on the computer (that’s the IBM Thinkpad’s way of doing it) and enable the serial ports (usually found under an Accessories or Devices menu).

If you went in to your BIOS and enable the serial ports, reboot and check the Device Manager tab again. Is your port there? If yes,then try out the software again!

Bare Minimum Configuration

By Bare Minimum Configuration, I mean that you don’t need any infrared device services, and you may not need a modem. This doesn’t mean that these devices are incompatible with this type of software, but troubleshooting a connection without these devices is much easier. Remove all unused accessories from the laptop at this time(Ethernet, Modem, etc).

Let me start off with an example, and perhaps this applies to you. I purchased an IBM Thinkpad 560 (P133, 40MB, 4GB). It’s a very nice laptop for in-car use, and I’d recommend it as a minimum level of laptop (it cost me $300). However, when I got the laptop, I loaded my software on it, and my software did not work. On this particular laptop, they don’t allow you to changeanything in the BIOS as far as serial port or infrared settings, so I had to do it all under Windows98.

So I started looking at the Device Manager, and noticed that the laptop had Infrared support. I noticed an Infrared serial port under Ports (COM & LPT), and also an “Infrared Devices” Heading on the same level in the tree as the Ports level. I also noticed that the Infrared devices were sharingthe same interrupt request line as the port on the back of the computer. That was what was killing me. So, I selected the infrared devices, one at a time, and disabled the device (under Windows98). See the box below – the second line from the bottom is the box I checked to disable the device.


So once I had disabled all of the infrared devices, I rebooted the computer. At this point, thecomputer came back up, and I looked at the Device Manager tab again. It showed one serial port – COM3. I tried out my cable and software, and what do you know – it worked on COM3. Hey, it’s working, so I stopped there. (

I did intend to travel with this laptop, and I had a PCMCIA modem, so I inserted the modem at this time. It automagically installed itself on COM1. No problem, since the modem...