Sony BVE-600 Maintenance Manual page 23

(9) EDIT PULSE
DATA BUS
eEach bit of GPI 1 thru. 3 are:
"1" RELAY close TTL OUT "L"
"0" RELAY open TTL OUT "H"
(0) CLUTCH AND BUZZER CONTROL
DATA BUS
Address
D2 D1 DO
9F001
BUZZER |CLUTCH
(PLAYER)
CLUTCH
(RECORDER)
3-5