E1330B: What is the difference between Models E1330B, E1458A and E1451A/E1452A?

These are all Digital I/O cards.

Models E1451A/E1452A have four 8-bit ports with 64K card memory behind each port.

Model E1330B has four 8-bit ports, and the E1458A has 12 8-bit ports with only one memory location behind each port.