[time-nuts] Serial port / Mouse issue (was mentioned in"Thunderbolt Monitor")

[Mike Millen]

Hal Murray wrote:
> stephen at tompsett.net said:
>> FTDI devices with their device driver should remember the COM port
>> they have been assigned on an individual system even if they get
>> plugged into  a different port/hub, and this greatly reduces
>> reconfiguration effort if  you change any USB connections - Other
>> manufacturer's devices have a  tendency to use a new COM port number
>> each time they are plugged into a  different physical USB port
>> connected to the same computer.
>
> The USB protocol has provisions for each device to provide a
> SerialNumber. That lets the OS connect them up at the appropriate
> logical name no matter which physical port they are plugged into.
> They have been common on disks and thumb drives for a long time.  My
> printer has one.  So does my scope.
>
> Most low cost USB serial adapters don't (or didn't) have a useful
> serial number.  (Or maybe the Linux drivers don't use it, but I
> suspect that's done at a higher level so it should work for serial if
> it works at all.)
>
> I have some FTDI adapters that produce useful serial numbers.
>   usb 3-1: SerialNumber: A4003UAg
>   usb 5-2: SerialNumber: A4001h2X
> I'm pretty sure I have other FTDI ones without a serial number.


On the FTDI website there's a (free) utility called FTProg which can 
reprogram the FTDI device.
You can set current limit, invert data lines, change description strings & 
serial numbers.
You can even set the serial number to be fixed for a number of similar FTDI 
devices so that they will all adopt the same Com port #, which can be 
useful, too.

Mike