A5 X2 Coder

End is Labeled:

A-5    X2    CODER                         100-101115
N        L            J           H          F         D  C  B  A
G        R           R           R          R         T  T  T   T
r          e            e            e           e         P  P  P   P
n         d            d            d           d


The X2A code is a shift register with the following equation:
1 + X1 + X3 + X4 + X5 + X7 + X8 + X9 + X10 + X11 + X12

The X2B code is a shift register with the following equation:
1 + X1 + X3 + X4 + X8 + X9 + X12

Where the exponents are the tap locations that are combined in an or gate and fed back to the input.

The X2 code is formed by the MOD 2 combination of X2A and X2B (i.e. a Gold Code).

I would expect to find a couple of 12 bit shift registers on this board with each bit's output brought out to a pin and some big OR gates and an external or gate to sum the codes.

Beckman  899-1-R270 F 93S47PC blank blank
AM25LS194PC 93S48 PC F 74LS32PC blank
AM25LS194APC F 93S47PC TI SN74LS123N blank
AM25LS194APC F 93S47PC header  rcrcrcrc blank
AM25LS194APC 93S48PC TI SN74LS123N TI SN74ls86n
AM25LS194APC f 93s47PC AM25LS163PC AM25LS151PC
AM25LS194APC bECKMAN  899-1-r1K AM25LS163PC AM25LS164PC
076-200089   prom? AM25LS09PC AM25LS163PC balnk
AM25LS08APC TI SN74128N DM74LS37N electrol cap