Call message recording for telephone systems

The standard exchange message interface (EMI) message record generated for interexchange telephone toll calls is enhanced via the addition of a primary interexchange carrier (PIC) indicator, whose value provides an indication as to whether a terminating subscriber has a particular interexchange carrier as his/her PIC. The PIC indicator may be used by the interexchange carrier when bills are rendered for its subscribers-for example, to provide different billing treatment for calls that were made over that carrier's network to terminating subscribers whose PIC is, in fact, that very carrier, as opposed to calls that were made to subscribers with a different PIC.