Hardware keyboard interfaces:

Primary J1:
1 VDD (3 to 15 Volts are OK, the logic level will change correspondingly)
2 KBD RESET
3 KBD CLOCK
4 KBD READ
5 LED RESET
6 LED CLOCK
7 Host RESET
8 GROUND

J2 is for connecting additional buttons or other devices:
1 VDD (pass-through from J1)
2-11 COLUMNS 0-9
12 ROW 7
13 ROW 8
14 GROUND