Hardware Interfaces  CMU 
1100.4903.12 8.10  E-8 
Connectors for Peripherals 
Printer Connector (LPT) 
The 25-pin standard Sub-D female connector LPT on the rear panel of the CMU is intended for 
connecting a printer. The interface is CENTRONICS compatible. 
 
1
14
13
25
D0
D1
D2
D3
D4
D5
D6
D7
ACK
BUSY
PE
SELECT
STROBE
AUTOFEED
ERROR
INIT
SELECT IN
GND
GND
GND
GND
GND
GND
GND
GND
 
  Fig. 8-5  Pin assignment of the LPT connector 
 
Pin Signal Input (I) 
Output (O) 
Description 
1  STROBE  O  Impulse for transfer of a data byte, 1µs pulse width at minimum 
(active LOW) 
2  D0  O  Data line 0 
3  D1  O  Data line 1 
4  D2  O  Data line 2 
5  D3  O  Data line 3 
6  D4  O  Data line 4 
7  D5  O  Data line 5 
8  D6  O  Data line 6 
9  D7  O  Data line 7 
10  ACK  I  Indicates that the printer is ready to receive the next byte (active 
LOW) 
11  BUSY  I  Signal active if the printer is unable to receive data 
12  PE  I  The signal is activated if no printer paper is available (active 
HIGH). 
13  SELECT  I  The signal is activated when the printer is selected (active HIGH). 
14  AUTOFEED  O  If the signal is active the printer inserts a line feed after each line 
(active LOW). 
15  ERROR  I  The signal is activated if no printer paper is available or an error 
occurred (active LOW). 
16  INIT  O  Initializing the printer (active LOW) 
17  SELECT IN  O  If the signal is active the codes DC1/DC3 are ignored by the 
printer (active LOW). 
18 - 25  GND    Connected to ground