Do USB com ports have designated #s

[stevethebrain]

Do USB com ports have designated #s



Last week I installed a boat engine diagnostic consisting of a piece of hardware that interfaces to engine diag. port and a software on DVD.

After configuring SW.

I installed EV Daig.s hardware I physically plugged the devise into a USB port. IIRC PC designated com port3. or could have been bc I just happen to choose that USB an it happens to be com3?



is this com3 a designated physical location USB port. My LT has 3 USB ports.so are they #ed com1/com2 an com3?
they must be bc when I installed the devise on com3 I'm thinking thats the only port this devise will function on.


Today I think I could have plugged the extension cable (which extends the devise) in a differnt USB port maybe thats why I could'nt connect to boat engines EMM engine management module? I thought the extension cable was faulty.



then accidently plugged into the correct USB minus the extension thats how I connected. bc I just tested the extension on a differnt PC an it works fine.

So next time I diagnose I’ll mark the USB port. Thanks for advising

 

[Trotter]

No, Windows does not designate USB ports by number. It can and does designate the connections from USB ports with COM/COMM numbers, but they have nothing to do with the physical ports themselves

Sounds mostly like either a flaky USB port, a flaky USB extension cable, or the software just doesn't like using the extension cable (could be losing too much voltage).

 

[stevethebrain]

No, Windows does not designate USB ports by number. It can and does designate the connections from USB ports with COM/COMM numbers, but they have nothing to do with the physical ports themselves

Sounds mostly like either a flaky USB port, a flaky USB extension cable, or the software just doesn't like using the extension cable (could be losing too much voltage).

so when I installed the hardware cable, it has the chip builtin. I could physicaly choose any 1,2,3 USB ports then when I interface I don't necessarily have to plug into the same USB port I installed the device on?
notice in lower left com3 open an bard rate. I believe open means connected to EMM bc below I have the dissconnect option.


last week when I recieved the diagnostics (EV Diag.) the extension was functioning however this was w/ engine turned off, I was basicely retrieving historical engine faults which I found which stay as undeletable files in the EMM data base.

I've tested the extension on a differnt PC it's functions properly.
yesterday I interfaced w/ extension I'm not exactly sure of the complete procedure (there are no instruction on operations or installation thanks ebay) I think it's
1.ignition key turn on 2. plug in interface 3.start program
if proper procedure isn't followed no connection to EMM error an not reconized USB devise.

yesterday what I was reduced to was removing the extension I also plugged into a differnt USB port but was able to connect to EMM notice RPM of engine is displayed.

will interface again today an be more observate of procedure an where I plug in.
basicely my ? was an I forced to plug interface into the same port I installed the devise on thus com3. thanks trotter will report back