4 USB TTL uarts on a USB hub - keeping them straight

[Robert Moskowitz]

Well, if I had a hub with more ports, I would have more of these, as I 
have more systems to interface with the serial console....

Anyway it seems that the dev assignment changes.  They are 
/dev/ttyUSB[0-3]  But at different times they are a different number 
which makes it hard to consistantly connect to the desired system.

Is there someway to identify the units and assign them permenant device 
names.  Much like is done with ethernet?