You could address this problem by writing a custom UDEV rule for every converter you want to use. This usually boils down to creating a text file in a specific location, typically /etc/udev/rules.d/*.rules
or something similar (depending on your distro).
I usually create symlinks to the device instead of renaming it... it is just easier and it allows me to abstract my devices from the operating system naming scheme. In the following an example of what you want to accomplish:
KERNEL=="ttyUSB*", KERNELS=="1-1.4", SYMLINK+="bridge0"
KERNEL=="ttyUSB*", KERNELS=="1-1.5", SYMLINK+="bridge1"
KERNEL=="ttyUSB*", KERNELS=="1-1.2", SYMLINK+="bridge2"
KERNEL=="ttyUSB*", KERNELS=="1-1.1", SYMLINK+="bridge3"
KERNEL=="ttyUSB*", KERNELS=="2-1.1", SYMLINK+="bridge4"
And now an example that leverages the serial number of the device instead (so the name is bound to the converter, not to where you connect it):
SUBSYSTEM=="tty", ATTRS{serial}=="FTFV8YRP", SYMLINK+="bridge0"
SUBSYSTEM=="tty", ATTRS{serial}=="A600N0ER", SYMLINK+="bridge1"
SUBSYSTEM=="tty", ATTRS{serial}=="FTZ2CBOD", SYMLINK+="bridge2"
SUBSYSTEM=="tty", ATTRS{serial}=="FTZ2CBVE", SYMLINK+="bridge3"
SUBSYSTEM=="tty", ATTRS{serial}=="FTZ29GWA", SYMLINK+="bridge4"
I have not encounterred the naming issue you mention when using Ubuntu 10.4 (a 2.6.3? kernel). As long as the same USB-serial adapters are connected to the same USB ports, I see the same device names. Review the system log, with 'dmesg' command, for the device recognition and name assignment. – sawdust – 2012-08-06T03:03:51.537