PIN  NAME      DIRECTION FROM PC

1  - !STROBE   OUT
2  - DATA 1    IN/OUT
3  - DATA 2    IN/OUT
4  - DATA 3    IN/OUT
5  - DATA 4    IN/OUT
6  - DATA 5    IN/OUT
7  - DATA 6    IN/OUT
8  - DATA 7    IN/OUT
9  - DATA 8    IN/OUT
10 - !ACK      IN
11 - BUSY      IN
12 - PAPER E.  IN
13 - SELECT    IN
14 - AUTO LF   OUT
15 - FAULT     IN
16 - INIT      OUT
17 - SELECT    OUT
18 - GND
19 - GND
20 - GND
21 - GND
22 - GND
23 - GND
24 - GND
25 - GND


ELECTRICAL CONSIDERATIONS

1.The open circuit Hi output should not exceed +5.5v
2.The open circuit Lo output should not be less than -0.5v
3.The DC Hi output should be at least +2.4v when sourcing 24mA
4.The DC Lo output should not exceed +0.4v when sinking 14mA

5.The receiver Hi input shall be no less than +2.0v
6.The receiver Lo input shall be no more than +0.8v
7.The receiver shall have between 0.2v and 1.2v input hysteresis
8.The receiver shall require no more then 20uA sink or source

PROGRAMMING

The port can be at one of three memory locations

378 - Ussually LPT1
278 - Ussually LPT2
3BC - MDA Printer Port

This is called the Base Address.  The port has three registers
called the Data Port, Status Port and Control Port.  Each is
one byte higher than the other with the Data Port being at the
Base Address.  A table of the different options is below.

Port Name   Base Address    Data Port       Status Port     Control Port

LPT1        0378            0378            0379            037A
LPT2        0278            0278            0279            027A
MDA         03BC            03BC            03BD            03BE

The Bits in each of the ports are shown in three tables below


Data Port

BIT     Direction   Pin#

Bit 0   I/O         2
Bit 1   I/O         3
Bit 2   I/O         4
Bit 3   I/O         5
Bit 4   I/O         6
Bit 5   I/O         7
Bit 6   I/O         8
Bit 7   I/O         9

Status Port

BIT     Direction   Pin#    Use

Bit 0   Not Used
Bit 1   Not Used
Bit 2   Not Used
Bit 3   In          15      Printer Status to PC
Bit 4   In          13      Printer Select to PC
Bit 5   In          12      Printer Out of Paper to PC
Bit 6   In          10      Acknowledge to PC
Bit 7   In          11      Busy to PC


Control Port

BIT     Direction   Pin#    Use

Bit 0   Out         1       Strobe to Printer
Bit 1   Out         14      Auto Line Feed to Printer
Bit 2   Out         16      Init to Printer
Bit 3   Out         17      Select to Printer
Bit 4   Not Used
Bit 5   Control     X       Selects Data Port Direction 0=IN
Bit 6   Not Used
Bit 7   Not Used
