6-1
Chapter 6 – Interfacing to Other Equipment
Interfacing the CAT-200B to your repeater system is a simple matter. A minimum of two inputs and two
outputs are required for the CAT-200B 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 to be 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-200B.
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-200B to
ON for (negative logic) and OFF for (positive logic).
Connection to Receiver
Connect the repeater receiver audio output to J3-13 and the COR to J3-6 of the CAT-200B. 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 a pull-up resistor to the COR #1 line. This may also be true for the COR #2
input. Space is provided on the CAT-200B board to add pull-up resistors.
Connection to Transmitter
Locate your repeater’s Push-To-Talk input. When grounded, this line will make the repeater transmit.
Connect the CAT-200B PTT #1 output (J3-10) 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 TX1 AUDIO (J3-
11) to this line.
Connection to CTCSS Decoder
If your repeater receiver has a CTCSS decoder output, connect it to J3-4. In addition to COR, the CAT-
200B requires an active high input to represent a CTCSS input. If the CTCSS input is active low set
dipswitch #2 on.
Interface Review
1. Are dipswitches #1 through #8 in their proper positions?
2. Is the PTT-1 output at J3-10 connected to the transmitter PTT input?
3. Is the TX1 Audio at J3-11 connected to the transmitter audio input?
4. Is the COR-1 at J3-6 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 VDC to greater than 3.0 VDC?
7. Is the RX1 AUDIO at J3-13 connected to the receiver audio output?
8. Is the audio input level sufficient for the DTMF decoder?
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