The PPS-4/2 (also known by its part number 11660) was a 4-bitmicroprocessor designed by Rockwell International and first produced at the 3rd quarter of 1975. The PPS-4 is part of the PPS-4 Family. The PPS-4/2 is the 2nd model from the PPS-4 family. The "/2" was used to indicate that this chip is a two-chip system; Rockwell incorporated the 10706 clock generator internally. It's full compatible with all the original PPS-4 CPU and all the other parts.
THe PPS-4/2 is functionally identical to the PPS-4. It can, however, directly drive low-power LED display.