DB-25 parallel connector pinout

Pin #	Function (standard mode)	Direction
1	Strobe	OUT
2	Data Bit 0	OUT
3	Data Bit 1	OUT
4	Data Bit 2	OUT
5	Data Bit 3	OUT
6	Data Bit 4	OUT
7	Data Bit 5	OUT
8	Data Bit 6	OUT
9	Data Bit 7	OUT
10	ACK	IN
11	Busy	IN
12	PE (Paper End)	IN
13	SLCT	IN
14	Auto Feed	OUT
15	Error	IN
16	Init	OUT
17	SLCT IN	OUT
18	Ground	-
19	Ground	-
20	Ground	-
21	Ground	-
22	Ground	-
23	Ground	-
24	Ground	-
25	Ground	-

Looking for parallel port low level C++ programming example ?
Download Unified IO and check out the class ParallelPort. It contains example of using PC parallel port to control Digital IO.