Link Communications RLC-4, Manual

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RLC-4 V1.79 Copyright © 1998 Link Communications Inc. 9/18/98
Controller to Computer or Modem Cable
Controller Description Computer Computer Modem Modem
DB-9 DB-9 DB-25 DB-9 DB-25
2 Data Out of Controller 2 3 3 2
3 Data Into Controller 3 2 2 3
5 Ground 5 7 5 7
Communications Parameters
After connecting your terminal, computer, or modem (either packet or telephone) to the RLC-4,
you need to make sure that the communications parameters match on both ends. The default
settings for the RLC-4 are 9600 N81:
Baud Rate 9600
Parity None (N)
Word Length 8
Stop bits 1
You can change the baud rate the RLC-4 uses with command 024. If you are using a modem, you
may be able to set the baud rate that the modem uses to communicate with the controller to be
different than the speed at which it connects to the other modem. In other words, a 2400 baud
modem may be able to connect to the controller at 9600 baud and to the other modem at 2400
baud.
Troubleshooting
If you can't get the connection between your computer or serial terminal and the controller to
work, there are several things you can check. Make sure that the serial cable is properly connected
between a serial port on your computer and the serial port on the controller and that the controller
is powered up. Load your communications software (Procomm, Telix, the Windows terminal
program, etc) and make sure it is set for the right comm port and baud rate. Whenever you reset
the controller (or cycle the power) it will output a serial message you should see on the screen.
Pressing enter should get you a "DTMF>" prompt that indicates that it is ready to accept the same
commands you might enter from a radio's DTMF pad. If neither the reset message or pressing
enter gets any response, double check that you have the comm port set right. Then disconnect the
serial cable from the controller and short pins 2 and 3 on that end of that cable together (those are
the data in and out pins). Then type on the keyboard and see if what you type shows up on the
screen - it should (even with echo turned off). If you quit shorting those pins, the data should not
show up on the screen. If you cannot get the data to show up on the screen by shorting those two
pins, the problem is either in the computer or the cable (the controller isn't even hooked up). The
most common problem is having the comm port set wrong - try all the settings. Then check your