Optional Counter Interface Unit Type M12 (B870-21) (MP 501/601 Only)
SM 2-43 D255/D256/M281/M282
11. Install the optional counter interface board [A] on the four stud stays.
12. Connect the harness (13 pins) to CN3 [A] on the optional counter interface board and
CN112 [B] on the BiCU.
13. Fasten the harness with the clamp [A].
14. Bind the harness with the harness bind [B] as shown below.