Using The Serial I/O Interfaces - NorthStar HORIZON Manual

USING THE SERIAL I/O INTERFACES
MODE CONFIGURATION
The RS-232 communication standard describes the interface between
Data Terminal Equipment (terminal) and Data Communication
Equipment (modem). If the HORIZON is communicating with a serial
terminal (such as a CRT, a teletype, or a hard copy printer) ,
then its serial interface must be configured to play the role of
a modem. If the HORIZON is comunicating with a modem, then it
must play the role of a terminal. Computer to computer
communication is possible if one computer plays the role of a
modem and the other computer plays the role of a terminal.
The HORIZON can also communicate with a 20ma current loop
terminal such as a teletype.
RS-232 CASES
A. HORIZON as modem
To interface to an asynchronous RS-232 terminal, jumper the
16-pin header at location 3D for the standard serial interface
(4D for the second Serial interface) as follows:
Connect pin 1 to pln 1 :2
Connect pin 2 to pin 16
Connect pin 3 to pln 15
Connect pln 4 to pin 14
Connect pln 5 to pln 11
Connect pin 7 to pin 8
Connect pin 9 to pin l~
A full 25-conductor cable must be used to connect the terminal
to the serial interface connector. Alternatively, the
following header configuration may be used with most RS-232
terminals. With this alternative configuration, a 3-conductor
cable between the terminal and computer connector pins 2, 3,
and 7 will suffice. The RS-232 control signals are not
connected, so serial communication applications which require
the control signals should not use this configuration.
Connect pin 6 to 2, 4, 5, and 12
Connect pln 7 to 8
Connect pin 9 to 10
B. HORIZON as Terminal
To interface to an asynchronous modem, the header at 3D for
North Star HORIZON Computer
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