IBM-PC Parallel Printer Port
Registers & Pinouts

Registers (- unavailable)

Pinouts

             Register  DB-25     I/O   
Signal Name    Bit      Pin   Direction
===========  ========  =====  =========
-Strobe        ¬C0       1      Output 
+Data Bit 0     D0       2      Output 
+Data Bit 1     D1       3      Output 
+Data Bit 2     D2       4      Output 
+Data Bit 3     D3       5      Output 
+Data Bit 4     D4       6      Output 
+Data Bit 5     D5       7      Output 
+Data Bit 6     D6       8      Output 
+Data Bit 7     D7       9      Output 
-Acknowledge    S6      10       Input 
+Busy          ¬S7      11       Input 
+Paper End      S5      12       Input 
+Select In      S4      13       Input 
-Auto Feed     ¬C1      14      Output 
-Error          S3      15       Input 
-Initialize     C2      16      Output 
-Select        ¬C3      17      Output 
 Ground          -     18-25       -   
(Note again that the S7, C0, C1 & C3 signals are inverted)

IBM-PC Parallel Printer Port Female DB-25 Socket external Pin layout

 ______________________________________________________ 
/                                                      \
\  13  12  11  10   9   8   7   6   5   4   3   2   1  /
 \                                                    / 
  \  25  24  23  22  21  20  19  18  17  16  15  14  /  
   \________________________________________________/   
So it's also the Pin layout on the solder side of the Male DB-25 Cable Connector that plugs into it