[lug] USB-to-Serial port assignment

Michael J. Hammel mjhammel at graphics-muse.org
Wed Jan 12 13:56:08 MST 2011

We've got a bunch of target boards that we connect to a host system via
USB-to-Serial connections.  USB on the host side, serial on the target
side.  The USB connections are through an external hub connected to a
host hub.  We use screen to connect to the USB ports on the host.  This
works fine until a reboot, when the USB port assignments may change.
ttyUSB0 might point to board A and ttyUSB1 to board B before a reboot,
but after the reboot they might be switched.   

Is there a way to force the assignments to remain the same?  If not,
anyone have any clever ways of figuring out how to identify the target
side of the USB/Serial connection short of running screen and testing
them manually?

My guess here is "no" - but I thought I'd ask anyway.

Maybe there is a way to connect multiple external hubs that we can
identify or the system will identify with different device file names?
Any mechanism of allowing use of lots of USB ports on the host to
connect to lots of external boards and being able to know which board
we're talking to when we connect to the USB device file.

Michael J. Hammel                                    Principal Software Engineer
mjhammel at graphics-muse.org                           http://graphics-muse.org
When C++ is your hammer, everything looks like a thumb.
              -- Steven M. Haflich

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