This board is used to decode the six device selector bits transmitted on the PDP-8, PDP-8/S or PDP-8/I negative I/O bus to select which addresses a peripheral responds to. The device code is selected by cutting diodes off the board. The selection diodes are the ones in the upper right next to the edge connector. The two on the handle is a stick on label used to mark what the low 3 bits of the address this board was set to, the upper 3 bits are normally the same for all boards in a peripheral. The full address this board is set to is 62 octal.
This board cost $52 in 1968.
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