Link Communications RLC-CLUB, User Manual, Page: 39 / 329

1-19
Version 1.73 Copyright © 1997 Link Communications Inc. 1/18/97
Example 1-2: Configuring a Port's COR/PL Polarity
In order for the controller to recognize a ports receiver:
The receivers COR signal is used to tell the controller when the receiver is active
An external decoder can be used to decode a receivers CTCSS 'PL' tone for controller access
Each one of these signals can be either high when active, or low when active.
What 'High' really means
A 'High' COR or PL signal indicates the input goes from a ground (0Volts) to either an open
(High Z) or to a voltage above 4 volts. The controller has protection that safely allows 'High'
voltages up to 15 volts without any damage to the controller. With a voltage meter you will
read a voltage on the COR and PL inputs with nothing connected. This indicates the input is
'Pulled Up'. An input is 'pulled up' so the controller always has a voltage on the COR and PL
inputs. This keeps the inputs from floating between 'High' and 'Low'
If you do not have a receiver connected to the controller, the controller will treat the COR and
PL active high. It is very important to tell the controller the COR and PL inputs are active low
if nothing is connected to the port.
What 'Low' really means
A 'Low' COR or PL signal indicates the input goes from an open or a voltage above 4 volts to
ground (0Volts). Ground does not mean open or nothing connected to a pin. Ground means
just that, ground or the same voltage and impedance as your power supply (-) terminal. The
controller has protection that safely allows 'High' voltages up to 15 volts without any damage to
the controller.
If you do not have a receiver connected to the controller, the controller will treat the COR and
PL active high. It is very important to tell the controller the COR and PL inputs are active low
if nothing is connected to the port.
Polarity Control
Once you have determined the ports COR and PL polarity you need to configure the controller
to accept the correct polarities. The controller defaults to active 'Low' on both the COR and PL
inputs of all ports. If your receivers are already 'Low' you do not need to change the
configuration. If you polarity is active 'High', you need to execute Command 013 and tell the
controller your correct polarity.
Active 'High' COR and active 'Low' PL (Or no PL at all) on Port 1 is configured as:
013 1 0 D or unkey (Refer to command 013 for more information)
This configured port 1 for active 'High' COR and active 'Low' PL