Link RLC-2 Manual page 15

Receiver De-emphasis Jumpers
J1 - Main Receiver De-emphasis Jumper
J2 - Link 1 Receiver De-emphasis Jumper
J3 - Link 2 Receiver De-emphasis Jumper
J4 - Control Receiver De-emphasis Jumper (J8 on Rev. A,B Boards)
- If type 2 audio is used, place the appropriate jumper in circuit (over both pins). This will place a -
6dB/octave de-emphasis filter into the circuit. Some discriminators can not directly drive the 10K
impedance. If this is the case, a pre-driver or different audio access point will be required. The filter will
not allow PL to pass through the controller. Contact Link Communications if your needs require PL to pass
through the controller.
- The audio input is connected to pin #5 of the male DB-9 connector (pin #6 for the control receiver).
- The audio adjustments will be described in Step #4.
How the DTMF Decoder Works
- The RLC-2's DTMF decoding circuit uses a scanner that enables the controller to receive tones from all the
ports, without mixing the three receiver's audio together. This allows the receivers to have total control of
the DTMF decoder when its COR is active. If the control receiver is active, and the control receiver is
configured for priority control, then the DTMF decoder is locked to the control receiver's port until its COR
goes away. Once the decoder has detected a tone on one of the ports, it stops scanning and waits up to three
seconds for the next digit. It is reset at the beginning of each DTMF digit. If any of the DTMF digits are
held for longer than 3 seconds or there is a pause of 3 seconds between digits, the DTMF scanner will
resume scanning and all digits entered up to that point are lost.
Step #4: Connecting Your Transmitters to the RLC-2
Transmitter PTT
- The RLC-2 produces an active low PTT signal (ground when PTT is active). This output is buffered with
an open collector type driver capable of sinking 150mA. There is a built in 30V zener clamping diode to
protect the PTT MOSFET from the high voltage spikes that can be caused by interfacing to a PTT relay coil.
Your transmitter PTT input should be connected to pin #3 of the DB-9 connector.
Transmitter Audio
- The RLC-2 provides a 10K
- The transmitter audio is connected to pin #4 of the DB-9 connector.
- If it is not already, the DB-9 plug can now be plugged into the appropriate jack on the main board. The
main repeater goes to the jack nearest the power jack, Link 1 is right next to it, and Link 2 is the third from
the left (with the DB-9s toward you).
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output impedance to your transmitter audio input.
Copyright 1995 Link Communications Inc.
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input