Ritron RIT17-445 用户手册
Connecting a 10K pot to ground at this point will allow the speaker volume to be adjusted. For maximum range the
internal AUX_OUT gain should be set to a value that allows maximum volume with acceptable distortion when the pot is
set at 10K. Optionally, this pin can be used as an RSSI output. If desired, contact the factory.
internal AUX_OUT gain should be set to a value that allows maximum volume with acceptable distortion when the pot is
set at 10K. Optionally, this pin can be used as an RSSI output. If desired, contact the factory.
Monitor Input (pin 11)
Normally the AUX_OUT and SPEAKER_ OUT are switched on only when a carrier with required tone, if
programmed, is detected. Bringing this input to ground will force the auxiliary and speaker outputs on. Alternately,
the monitor input can be used as an output. It gets pulled low when a carrier with correct tone is detected. The
following circuitry can be used as a carrier and tone detect output. Pin 11 can still be pulled low to monitor the
channel. Notice the high impedance 470 k ohm buffer resistor. Too low of resistance will turn the audio on.
Normally the AUX_OUT and SPEAKER_ OUT are switched on only when a carrier with required tone, if
programmed, is detected. Bringing this input to ground will force the auxiliary and speaker outputs on. Alternately,
the monitor input can be used as an output. It gets pulled low when a carrier with correct tone is detected. The
following circuitry can be used as a carrier and tone detect output. Pin 11 can still be pulled low to monitor the
channel. Notice the high impedance 470 k ohm buffer resistor. Too low of resistance will turn the audio on.
Pin 11
470 k
15 k
Tone detect = 0
Vdc
15 k
Tone detect = Vdc
External circuit to use AUX_MON input as Tone Detect output
Speaker (pin 12)
An 8 ohm or higher speaker should be connected to pin 12. One watt of audio power is possible. The speaker volume is
set via the programmer AUX_OUT gain. The output signal can be further attenuated by a fixed or variable resistor from
pin 10 to ground to attenuate the audio.
Carrier Detect Output (pin 13)
This line will be pulled to 3.3 volts through an internal 390 ohm resistor when a carrier is present. This output is carrier
detect only. It gets pulled high at the same time the green LED lights.
Push-To-Talk (pin 14)
Pulling the PTT input low activates the transmitter, and must be held low while transmitting. Alternately, a microphone
with a PTT switch (switched to ground through < 3 k ohm) can be connected to pin 4 to activate transmission. A
programmable time-out-timer will shut down transmission when PTT is held down too long.
12