Table 1, Pin Assignments from ANSI X3.101
Signal	Ground	
Pin	Pin	Signal Name				Signal Source
----------------------------------------------------------------------
1		Ground					---
		CONTROL BUS
2	10	  Bit 0, Select Attn Device 0		Host/Device
3	10	  Bit 1, Select Attn Device 1		Host/Device
4	10	  Bit 2, Select Attn Device 2		Host/Device
5	10	  Bit 3, Select Attn Device 3		Host/Device
6	10	  Bit 4, Select Attn Device 4		Host/Device
7	10	  Bit 5, Select Attn Device 5		Host/Device
8	10	  Bit 6, Select Attn Device 6		Host/Device
9	10	  Bit 7, Select Attn Device 7		Host/Device
11	12	  Parity (optional)			Host/Device

13	14	SELECT OUT/ATTN IN STROBE		Host
15	16	COMMAND REQUEST				Host
17	18	PARAMETER REQUEST			Host
19	20	BUS DIRECTION OUT			Host
21	22	PORT NABLE				Host
23	24	ADDRESS MARK CONTROL (optional)		Host
25	26	READ GATE				Host
27	28	WRITE GATE				Host
29	30	BUS ACKNOWLEDGE				Device
31	32	INDEX					Device
33	34	SECTOR/ADDRESS MARK DETECTED		Device
35	36	ATTENTION				Device
37	36	BUSY					Device

39	38	READ DATA +				Device
40	38	READ DATA -				Device
42	41	READ/REFERENCE CLOCK +			Device
43	41	READ/REFERENCE CLOCK -			Device
45	44	WRITE CLOCK +				Host
46	44	WRITE CLOCK -				Host
48	47	WRITE DATA +				Host
49	47	WRITE DATA -				Host
	50	Ground					---