AP Mainboard 26 pins connector rear end. 01 AF for tone 02 +12 Main power input 03 +12 Main power from switch 04 +5V keyed, also yellow wire to relay box 05 +5V supply 06 Handset speaker 07 External Alarm 08 +12V keyed 09 Mod amplifier block 10 Display ones 1 11 Display ones 2 12 Display ones 4 13 Display ones 8 14 Display tens 1 15 Display tens 2 16 Display tens 4 17 Display tens 8 18 Handset key input 19 Handset Mic input 20 Free 21 Free 22 +12 for display must be connected to pin 3 23 +12 for lamps must be connected to pin 3 24 +12 supply must be connected to pin 3 25 Speaker output 26 Dynamic Mic input Downloaded fra www.webx.dk/oz2cpu/