The E1451A and E1452A are identical except that the E1451A passes along the Local Bus pattern clocks to the next module whereas the E1452A terminates the pattern clock lines. The E1452A Terminating Pattern I/O Module must be the last module of the Pattern I/O module set so the Local Bus is properly terminated when the E1450A Timing Module is used. If external timing is used in lieu of the timing module, then only E1451A Pattern I/O modules are required.
The Agilent E1451A Pattern I/O Module is a single slot C-size VXIbus register-based module. It is used to send or receive pattern data from the DUT. Each I/O module contains four identical 8-pin ports (32 I/O pins). Each port can be independently programmed to either output (stimulus), record (response), or real-time compare. Bidirectional I/O is created by connecting the I/O pins of two or more ports together.