A pre-designated inter-exchange carrier transports traffic that originates in one LATA and terminates in a different LATA. Each line or trunk must show a pre-designated inter-exchange carrier.

A PIC Freeze (Primary InterExchange Carrier Freeze) is an option with your LEC (Local Exchange Carrier, or local phone company) to block your telephone line(s) from being switched to another long distance carrier without your prior authorization.

How it works:

In order to place a PIC Freeze on your line(s) all you have to do is call your local phone company and ask them to do this.

What to do if I have a PIC Freeze and wanna change long distance carriers?
If your line is blocked by a PIC Freeze and you wanna sign up for a new long distance service first you should call your local phone company and ask them to remove the Freeze. Then you can sign up for the new plan, and when your service is active you can reinstate the Freeze to prevent unauthorized switching of your line (slamming).