Megan asks: Only what's in the KA630-AA CPU Module User's Guide On pages 2-7 and 2-8, it says that switches 7 and 8 of the KA630CNF preform that function, and that they are wired to KA630-AA J2 pins 4 and 5, which are called "CPU CD0 L" and "CPU CD1 L". The switch settings are documented as KA630CNF switch 7 8 CPU Operation Mode KA630-AA J2 pin 4 5 Off Off Arbiter [normal] On Off Auxilliary 1 Off On Auxilliary 2 On On Auxilliary 3 So I'd guess that if you grounded J2 pin 4, your KA630 would become Auxilliary 1. Ground is available on J2 pins 1-3, 6, 12, and 16. Other switch settings are: KA630CNF switch 1 Halt Mode KA630-AA J2 pin 15 Off Disabled On Enabled KA630CNF switch 2 3 4 Console Baud Rate KA630-AA J2 pin 17 18 19 Off Off Off 300 On Off Off 600 Off On Off 1200 On On Off 2400 Off Off On 4800 On Off On 9600 Off On On 19200 On On On 38400 KA630CNF switch 5 6 9 10 Power-Up Mode KA630-AA J2 pin 13 14 Off Off On Off Normal Operation On Off On Off Language Inquiry Mode Off On Off On Loopback Test Mode On On On Off Manufacturing use only, bypasses memory test Notes: According to the manual, other settings for switches 5, 6, 9, and 10 should not be used. The manual lists switches 9 and 10 as being connected to KA630-AA J3 pins 3 and 8. However, I suspect that they are wired such that switch 9 when off disconnects the normal receive input, and switch 10 when on connects the loopback. I don't have prints to confirm this. The diganostic LEDs are driven by J2 pins 7, 8, 9, and 11, with 11 being the most significant bit. +5V is available on J2 pin 20. +10V is supplied from the BBU (battery) to the TOY (real time clock) via J2 pin 10.