Boundless Technologies 4000 - Manual (Page 26)

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.
DTE
SES1 EIA
Modem
Transmit
Receive
DTR
DSR
Transmit
Receive
DTR
DSR
pin2
pin3
pin20
pin6
pin2
pin3
pin20
pin6
D
C
E
Host
DCE
SES2 AUX
Modem D
C
E
Host
Receive
Transmit
DTR
DSR
Transmit
Receive
DTR
DSR
pin2
pin3
pin20
pin6
pin2
pin3
pin20
pin6
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).