Running cp210x VCP driver 3.1 on 10.8 Mountain Lion and every time the USB device is disconnected/connected the device name(s) change. There are two USB-UART chips in the box we are connecting and the one device is always /dev/tty.USBtoUART, but the other one has a number at the end and it changes each time (5, 7, 10, 12, 14...I don't know how high it's going to go . Is there a way to stop this? We have to keep telling the software on the Mac that is trying to talk over the two ports to keep scanning for the ports so it knows which ones to use. I think this has been going on since OSX Tiger days, but we haven't been using this equipment with OSX for a while. It's normally Windows, but (apparently) the VCP driver in our Windows machines is causing big trouble (crashing, dropping the COM ports, etc). At least now you don't have to keep rebooting the Mac to get the devices to show up like you did back on Tiger. They seem to come and go just fine, and talking seems to be OK. It's just this naming problem.
The VCP driver is most closely related with the Interface product line (CP210x). I've moved your post to this forum so that those familiar with the interface devices and driver can find it more easily.
How to fix this issue? I meet same problem with CP2108 on MAC. When I unplug the USB and plug again, the name of 2~4 UART name will change.