A PIC or CIC code is a 4-digit prefix that identifies a long distance carrier in North America or the Caribbean to a LEC. The LEC uses the code to properly route the call.
Many PIC and CIC codes can be manually dialed before placing a long distance call by dialing 101 followed by the PIC/CIC code. This forces your call to be carried by that PIC/CIC code's carrier instead of your normal long distance carrier.
Bell Atlantic Communications
May 22, 1984