From the MITS Altair 680B schematic,
Herb Johnson July 19 2020, fixed May 20 2022

00	GND
01	+5V
02	 
03	A10
04	A11
05	R/W
06	 
07	A9
08
09	A7
10
11	A6
12	A5
13	+9V
14	R/W-P
15	A3
16	PHI1
17	A2
18	
19	A1
20
21
22
23	A4
24	/NMI
25	A12
26	-9V
27	BD0
28	BD1
29	DBE
30	A14
31	BD2
32	A15
33	/TSC
34	D7
35	D3
36	/IRQ
37	D6
38
39	D5
40
41	D4
42	BD5
43	BD6
44	BD7
45	
46	D1
47	D0
48	
49	2MHZ
50	GND


51	+5V
52
53	A8
54	/RES   reset
56	A13
57	PHI2
63	/HALT
71	A0
72	-16V
76	+18V OR +16V
81	BD3
90	BD4
95	D2
96	/IRQ
97	BA
98	VMA
100	GND