Re: [A/S] GPS Use

[Rick Kunath <k9ao@xxxxxxxxxxx>]

All three of the USB ports on the computer are the same, they are not 
different ports like COM ports are, in other words, it makes no 
difference which one you hook up to, and moving to another USB port 
won't fix any issues unless you actually have a bad port or port connector.

You won't see a USB device by looking at COM ports in the M$ device manager.

Not all software is compatible with "virtual" COM ports created by USB 
to serial adapters. Microsoft Street and Trips older versions are not 
compatible with these adapters.

Your COM 5 would be a "virtual port", and not an actual hardware port. 
Do you actually have a third (COM 3) hardware port or has some device 
created a "virtual" port? Or, is COM 3 the hardware port residing on 
your landline modem? (In which case you can't access it with any 
external device.) Laptop modems will usually grab COM 2 as there isn't 
any hardware port on the laptop motherboard using this resource. If this 
is the case, COM 3 may be a "virtual" port.

COM 1 and 2 (your desktop likely has 2 COM ports, though one (COM2) may 
not be brought out to the case rear, and may be accessible via a 
motherboard header), are actual hardware COM ports with motherboard UART 
RS-232 line drivers. COM 2 can be brought out to the rear case panel 
with a $2 adapter plate and cable.

Laptops almost universally have but one hardware COM (COM 1) port.

COM 3 and 4 on desktops are usually actual hardware ports residing on 
cards such as a modems and other expansion cards. Keep in mind that 
hardware COM 3 and 4 ports (but generally not "virtual" ports in this 
range) share motherboard interrupts with COM 1 and 2, so if you are 
using COM 1, you can't use COM 3 at the same time, and the same goes for 
sharing COM 2 and 4. You can use 1 or 3, and 2 or 4, but not at the same 
time. Virtual ports behave somewhat differently depending on how your 
particular motherboard and BIOS manages shared interrupts. But this can 
get problematical if things aren't done right.

Ports above COM 4 are in most cases "virtual" ports. USB to serial 
adapters create these "virtual" ports which not all software can recognize.

Bottom line, if it fails to work with USB, the software should probably 
be upgraded if possible. There is no guarantee that "virtual" ports will 
work with a particular piece of software. And to complicate things 
further, not all laptop USB ports are capable of supplying the current 
draw some USB to serial converters require. Powered USB hubs may solve 
this, but you're fast getting to the point where you're adapting 
adapters, and you're in for trouble.

Update the software to a version that natively supports USB if possible, 
or use a serial capable GPS. My Garmin units will do USB or serial.

Rick Kunath
WBCCI #3060