Hiway DMA card for the Data Hiway Port, processes read and write commands through DMA, and is the card where the box address is set.

This board contains 2 LEDS:
Upper LED - On or blinks for callups to this DHP Lower LED - On or blinks for data read/write

Board contains 2 sets of Switch Packs for Polling(S2,S3) and 1 set for Addressing(S1). 

Address Switch Pack
_     _     _     _     _     _     _     _
| |   | |   | |   | |   | |   | |   | |   | |
| |   | |   | |   | |   | |   | |   | |   | |
|_|   |_|   |_|   |_|   |_|   |_|   |_|   |_|
P     S     B     16    8     4     2     1
|     |     |
|     |     |
|     |     |__ BA + 32, PIU expansion bit
|     |         "Set" for PIU with 3 or 4 PCFA's
|     |         "Reset"  for PIU with 1 or 2 PCFA's
|     |
|     |________ Spare, always "Reset"(0)
|
|______________ POLL, normally "Reset" only "Set"
to force PIU to respond to all 
Hiway polls during adjustment of 
poll delay time. Reset when adjust
is complete.
*A1