Boundless Technologies 4000 Benutzerhandbuch

Communications     11

 

Parallel Printer Port 
This port, labeled “PAR,” is designed for connection to a parallel printer, which has a 
Centronics interface with a 25-pin D-shell female connector.  This port, unlike the 
others, is a uni-directional device—it only serves to output data to the printer and 
cannot receive data.  The pins and signals supported are shown below: 

 

Parallel Port Pin Assignments 
*  These signals are held high, in an inactive state. 

 

If you have opted to use a parallel printer, but it is not connected, an error message 

will appear on the status line when any PRINT operation is done.  This error will not 
affect your terminal’s operation.  Any activity that updates the top status line (such as 
pressing the 

CAPS LOCK 

key) will clear the error message.   

Terminal to Modem (DCE) or Host 
Refer to the diagram below to understand why a null modem adapter may be needed 
when connecting the second serial port (SES2-AUX) to a modem or a DCE host.  The 
first serial port will connect directly without a null modem since it is a DTE device.  

 

 

Terminal to Host (DTE) or Printer 
Refer to the diagram below to understand why a null modem adapter may be needed 
when connecting the first serial port (SES1-EIA) to a host port or a modem.  The 
second port (AUX) will connect directly, without a null modem, since it is a DCE 
device (most serial printers are DTE devices).