Com port issue on win 10 surface pro

[rcfant89]

I'm having an odd issue I can't figure out. I've got a usb to serial cable to interface with legacy telecom equipment. I've got a handful of surface tablets but can only get it working on one of them.

The error I get is this:

Problem is, the surface won't even check, it just instantly gives that error. I went through the trouble of matching the exact same driver, it's the same surface model, same win 10 build, same cable. One of them works though, and the other just instantly gives that issue.

As previously mentioned, I've got a few more of these tablets I need to get working as well and it's only working on the one and I'm not sure why. Thanks.

 

[gdmaclew]

If you clone the working one to one of the tablets that's not working what happens?

 

[rcfant89]

I haven't tried that (yet) but seems like a big step just to get the com port to work.

 

[Solandri]

Haven't had to diagnose a COM port issue in over a decade...

You may be suffering a COM port conflict. I've noticed some USB to serial devices hard-code which COM port they're to use. If another device is using the same port, it could cause the issue you're seeing. Try going into the driver properties and see if you can change it to use a different COM port. Or if it can only use the one COM port, see if you change the conflicting driver to use a different COM port.

 

[gdmaclew]

I haven't tried that (yet) but seems like a big step just to get the com port to work.

If you have multiple identical units to set up it would make sense to have an image you can copy to each one. This way you will know for sure that each one has identical software.

 

[rcfant89]

That's a good idea. I tried it though and it didn't work. Changed it to com1, then tried back to 3 then to 9. The app instantly says rejected though like it's not even checking the com port.

 

[gdmaclew]

Something is very slightly different on the machines that don't work - either software or hardware.
The quickest way to tell this is to create an image of the one that works and copy it to one of the machines that doesn't.
If it still doesn't work, you know it's a hardware issue.