Pin out for the power connector on the rear of the radio is as follows:
#1 N/C
#2 HANG UP BOX
#3 HANG UP BOX
#4 OPTIONAL - EXTERNAL SPEAKER
#5 JUMPER TO # 6 WHEN USING INTERNAL SPEAKER
#6 OPTIONAL - EXTERNAL SPEAKER
#7 GROUND
#8 N/C
#9 + 12 v
We can program this radio along with most other older commercial two way radios.