Connector:Aux socket (CPC Plus only)
From CPCWiki - THE Amstrad CPC encyclopedia!
Aux Socket (6 pin RJ-11 type, Western???) (CPC Plus and GX 4000 only)
This port combines the expansion port's LPEN signal and the joystick ports Fire signals. Invented to make it easier to connect a light gun (especially since the GX 4000 doesn't have an expansion port). Used for the Trojan Light Phazer.
1 +5V 2 /Joystick1 ??? 3 Light Pen (Trojan Light Phazer: Light sensor) 4 /Fire 2 (Trojan Light Phazer: Trigger button) 5 /Fire 1 (Trojan Light Phazer: Not used) (could be menu/mode button) 6 Ground
Pin 1 is the leftmost, and Pin 6 is the rightmost pin.