Specifications

7-1
Chapter 7 - Interfacing to Other Equipment
Interfacing the CAT-1000B to your repeater system is a simple matter. A minimum of
two inputs and two outputs are required for the CAT-1000B to control a repeater. They
are:
1. A COR signal to indicate when a signal is being received.
2. A receive audio signal containing DTMF tones too processed for control.
3. A Push-To-Talk signal to tell the repeater transmitter to turn ON.
4. A transmit audio signal containing a combination of receive audio, synthesized
voice, and courtesy tone.
Additional connections are required to realize all features of the CAT-1000B.
Determining COR Logic
Locate your repeater receiver's COR output. This line has a DC voltage that changes
state when a signal is being received. If the COR line is 0 volts and goes to a
positive voltage when a signal is received it is said to be (positive logic) or active
HIGH. If the COR line is a positive voltage, and goes to 0 volts when a signal is
received it is said to be (negative logic) or active LOW.
Note: 0 volts is any voltage less than 0.8VDC. A positive voltage is any voltage
greater than 3.0VDC. Set dipswitch #1 on the CAT-1000B to ON for (negative logic) and
OFF for (positive logic).
Connection to Receiver
Connect the repeater receiver audio output to J4-13 and the COR to J4-6 of the CAT-
1000B. Measure the COR level when the receiver is active. Verify this line changes
from less than 0.8VDC to greater than 3.0 VDC. If the COR line will not meet these
limits it may be necessary to add an external pull-up resistor to the COR #1 line.
This may also be true for the COR #2 and CTCSS inputs.
Connection to Transmitter
Locate your repeater's Push-To-Talk input. When grounded, this line will make the
repeater transmit. Connect the CAT-1000B PTT #1 output (J4-10) to this line. Locate
your repeater's TX audio input. This is the line were the audio signal used to
modulate the transmitter is applied. Connect the TX #1 AUDIO (J4-11) to this line.
Connection to CTCSS Decoder
If your repeater receiver has a CTCSS decoder output, connect it to J4-4. In addition
to COR, the CAT-1000B requires a positive logic input to represent a CTCSS input.
Interface Review
1. Are dipswitches #1 through #8 in their proper positions?
2. Is the PTT #1 output at J4-10 connected to the transmitter PTT input?
3. Is the TX #1 Audio at J4-11 connected to the transmitter audio input?
4. Is the COR #1 at J4-6 connected to the repeater receiver COR output?
5. Is dipswitch #1 ON for active low COR or OFF for active high COR?
6. Is the COR level changing from less than 0.8 too greater than 3.0 VDC?
7. Is the RX #1 AUDIO at J4-13 connected to the receiver audio output?
8. Is the audio input level sufficient for the DTMF decoder?