NEC 1 ISDN PRI daughter board - IP7WW-1PRIDB-C1 The 1PRIDB-C1 daughter board is mounted on the 082U-B1, 008U-C1 or 000U-C1 board and installed on the Universal slot in the IP7[ ]-4KSU-C1 chassis and provides either an ISDN Primary Rate Interface, T1 Interface or E1 interface. A total of three 1PRIDBs can be installed per system or one 1PRIDB per Chassis