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

 

[PP Mguire]

The cable is a device meant to connect to your ECU via a serial connection, it's not a standard USB connection, that's why it says COM3. Typically on laptops Type A ports are all wired to the same USB chipset which is internal to the CPU, while any USB C ports typically have their own chipset.

In your case I think Trotter is right, there might be too much voltage drop with the extension on a specific port. Process should be plug USB into ECU, open your software, turn ignition to ON position (power, not start) and the software should start reading.

 

[stevethebrain]

tryed to interface again to scan the engines EMM. the USB extension was flaking out majorly. I have a cheap USB extension. if I upgrade to a better cable like this maybe I'll get connectivity?thanks

https://www.amazon.com/gp/product/B07ZV6FHWF/ref=ewc_pr_img_2?smid=A3ISN3IGK0NJQ9&psc=1

 

[stevethebrain]

ok I interrupt the like as a yes?
additionally the manufactor of there interface cable is sending a replacement, an I will send back this problem cable, BC comport2 flakes out even w/out the extension an just the ft232 interface cable. thanks Trotter will report back w/ results.being 10/15 miles offshore in the gulf of America gotta make sure the engine is seaworthy.

 

[Ste]

Sorry I am little slow at times., but isn't this just a try a different USB port, or maybe you need a USB hub?

Perhaps motherboard needs firmware update? I'm just randomly typing words/guesses.

 

[stevethebrain]

Sorry I am little slow at times., but isn't this just a try a different USB port, or maybe you need a USB hub?

Perhaps motherboard needs firmware update? I'm just randomly typing words/guesses.

yes the initial log on thats when I was able to connect just switching usb ports on PC but still a bit flakey.
back in the good ole days these interface cable where made w/ a little quality now it's somebody in a dusty backroom slopping them together.
hopping the next cable an addition of a quality USB extension cable I'll be able to connect an stay connected.
I say stay connected bc she will sometimes connect just won't stay other times can't connect. will report back they 2dayed shipped the new cable.

this LT USB ports function fine w/ other devices connected.

what I'm still a bit confussed on is when configuring the ft232 UART cable when I plug cable in during SW configuration is that port an only that port com2?
here's a quickie video on the configuring setup of the UART interface cable I doubt it but maybe I missed something basicely I took notes on each step. thanks

https://rumble.com/v6ks2d7-ev-diag-setup-procedure.html




thanks

 

[Ste]

Seems like you got it or are on the track to figuring it out. Otherwise try the forums for the manufacturer of that Motherboard and/or USB Drive. Otherwise you've re-defined my head and flew over it 5 times in different crafts. - Shrug Emoji -