Unit installation

1-18

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 change the labeled switch on the appropriate radio card

to tell the controller your correct polarity.