PG is a device which facilitates direct linkage between the Participant Supplied System (PSS), the Participant’s back office system and CCASS/3. Using the PG access mode, CCASS/3 functions are performed by the transmission of standard messages. Transactions input to the PSS can be routed to CCASS/3 directly, without the need to re-input to CCASS/3 via C3T. Since PG supports straight-through-processing from PSS to CCASS/3, it is most useful for high volume data exchange where the same data already exist in PSS.