Hello.
Using /etc/remote you can access serial RS-232 ports.
What do you want to do?
If you want to use an USB-to-RS232 converter you must have a device driver for that. Unfortunately most of those devices only come with drivers for Windows. If you have a driver (or if the adapter is already supported by Solaris) it has an entry somewhere in "/dev" so you just do something like "tip ... /dev/usb/term1" (or whatever the name of the device in /dev is).
You cannot use tip to just communicate to any USB device.
Martin