Digital Camera Home > The Imaging Resource's Tip for Troubleshooting PC Serial Port Camera Connections
Getting the camera to talk to your computer!

This is one of the most-common subjects on our discussion forum. (Or at least it was, until Gerald Payne generously wrote this excellent little debugging guide. :-)
PC serial ports are notorious for being a non-standard "standard" connection, as they're often difficult-to-impossible to get working properly. All sorts of seemingly unrelated things can cause them to malfunction, making getting your new digital camera and old computer talking anything from a walk in the park to a hair-tearing experience.
Reader & Q&A-forum regular Gerald Payne kindly took the time to walk through a typical debugging process to get your camera up and running. If the process described below doesn't work, you may want to consider an separate card-reader to just pull images from your digicam memory cards directly. (But then, that's a topic for another FAQ...)
Do you have relevant experience that might save someone else hours of effort? Click the link here and leave it as a comment! Don't be bashful, the little detail that finally got your camera working might be just the tidbit someone else needs to save them hours of frustration!
Have an idea for a FAQ? Receive fame & fortune (much more of the former than the latter, unfortunately) by writing it up for The Imaging Resource! Email us at [email protected] with your idea, and help the community!

Troubleshooting PC Serial Port Camera Connection Problems
(or How I Spent My Life... Well, it seemed like it!)
by: Gerald M. Payne


Background: (Or stating the remarkably obvious:)

Many digital cameras are designed to connect to a computer through a serial port. This can often be a source of problems since one has limited resources in a PC and ports may not be available, connected, or properly configured. The average PC is set up for up to 4 physical serial port connections, each of which is provided with a software driver called a COM or communications port. For the most part, Serial and COM ports can be thought of as the same thing by the average user. Typical serial peripherals are modems, mice, and digital cameras. Internal cards (mostly modems) also use COM ports.
First things, first:

Make sure that your camera is turned on and properly set up. Check your manuals to make sure you have the cables connected properly and that you have the camera set to the proper mode or menu option to transfer images to your computer. Make sure the batteries are fully charged or use an adaptor. If you have an option to turn off the LCD display you might want to do that to save power if you're running off batteries.
PC serial ports are usually terminated in a 9 or 25 pin connector mounted on the back of the PC's case. These ports are relatively easy to identify since they are typically the only 9 and 25 pin ports that have pins rather than sockets.
If these basic items can be checked off your list it's time to shut the camera off and check the Windows port settings.

Checking the Com Port's Setup in Windows 95 & 98

Click the [Start] button on the Windows desktop, highlight Settings, then select Control Panel. Double click the Computer icon, select the View Resources tab and select Interrupt request (IRQ). This will display the Computer Properties dialog and a list of your PC's Interrupts or IRQ's. Interrupts are just what they sound like, a signal that interrupts what the processor is doing and says "Hey! Look at me." Each Com port will ideally have it's own Interrupt number. If two ports share an interrupt they can't both be used at the same time. In some cases one may not work at all. Scroll down through the list and make a note of each COM port and what IRQ it uses (the number in the left column) and also make a note of which IRQ your modem uses, if you have one(bet you do if you're reading this...). Now look for unused IRQ's. There are 16 IRQ's labeled 0-15, if unused they won't appear in the list. Make a list of any unused IRQ's. If all your COM ports use a separate IRQ, it's time to go back to the drawing board. If not, cancel the Computer Properties dialog and go back into the device manager. At this point you must assign the COM port you wish to use an unused IRQ or disable another device and use it's IRQ.
Select the + next to Ports and then select the COM port you'd like to change and press the Properties button. Click the Resources tab and highlight Interrupt Request and then unclick the checkbox next to Use automatic settings. Now you can click the Change Setting button and select the IRQ you wish to use. You'll probably have to reboot in order for the changes to take effect.

Swapping Cables

At this point you should try the image transfer again and see what happens. If you're still unsucessful, try swapping your mouse(assuming you have a serial mouse) with the camera cable and rebooting to see if your PC can find the mouse. If it can you have at least proven that the port you were trying works. If it doesn't go back and check that port out again and make sure there are no conflicts displayed in the Settings dialog. If you've gotten the mouse working on the other port then the next step would be to try the camera software again with the cable connected to the port that you were originally using for the mouse. You might have to re-install the software or manually configure it to use the port. You might even need to reboot again to get all the details worked out so that Windows and the image transfer program both know where everything is connected.

Last Resorts

If you've followed along carefully by this point you've eliminated all the simpler and obvious pitfalls. If you still can't get your mouse to work on the other port move it back to the original position and shut your system down. Open the case and make sure that the cable for the port you can't get working is physically connected at both ends and that it's plugged in the right direction on the motherboard. You can usually determine this by looking for a notch or mark on the motherboard and matching a stripe on the cable up with it, or by looking at how the cable for the port that works is connected. If it all checks out, button up the case and reboot. Stop your PC during the bootup and run the system monitor program for your BIOS. This is usually done by waiting for a message that says "Press DEL for setup menu" during the boot up process and then pressing the key before the BIOS goes to the next step in the Boot up process. You might be able to find settings in this program that let you set how your communication ports are configured or if they are activated at all. Make sure you know what you're doing if you attempt this. Incorrect settings could prevent your PC from booting properly or keep Windows from running at all. If you do change any settings make a note of which ones and make sure you save the changes before exiting your setup program. Reboot and try it again.
If you're still unsucessful it's time to think about consulting the camera's manufacturer and their service department or a local technician to determine just what your problem may be. Better yet, buy a media reader and save yourself a lot of grief.

Up to Imaging Resource "Tips" page

Up to Imaging Resource Digital Camera Reviews

Up to Imaging Resource Home Page