ZETRON Model 25, Руководство по эксплуатации продукта

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Encoder Installation
025-9567E 43
The input impedance of each input is selectable internally between high and low impedance.
The subsection “Inside the Encoder” describes the way the impedance is selected.
Audio Output/Muting
The audio section of the Model 25 consists of a balanced 600 Ω audio output and a DPDT
audio muting (switching) relay. The audio muting relay will close (common connects to
normally-open) when encoding or alerting tones are being generated. This allows the console
microphone to be muted (transmit audio switched from the console microphone to the
encoder audio) when a calling sequence is in progress. The output impedance of the Model
25 may be increased to match that of a high impedance microphone by adding a series
resistor. Many consoles provide an auxiliary audio bus meant specifically for encoder audio.
If this is the case then connect the audio output to the auxiliary audio bus rather than the
microphone input.
The audio output level is adjustable via the trimmer potentiometer, R20, which is accessible
through the hole in the back panel. The output level may be increased by turning the
potentiometer clockwise. The adjustment range is either -60dBm to -10dBm or -60dBm to
+10dBm depending on the presence or absence of a resistor on the inside of the encoder.
Please see “Audio Level Adjustment Range” on page 35 for details on selecting the range.
The audio emphasis is shipped from our factory to give one pole (6dB/octave) of de-
emphasis over the frequency range 250 to 3276 Hz. However, pre-emphasis or flat response
may be added by the alteration of jumper JP5 and two components on the inside of the
encoder. Please see “JUMPER AND SWITCH SETTINGS” on page 37.
Tone Monitor
A 0.2 W monitor speaker is provided inside the encoder. The output level to the speaker is
adjusted by potentiometer R19, accessible from the encoders rear panel.
The speaker drive output is available on connector P1-1 and P2-1 labeled “TONE OUTPUT
2A/B”. The internal speaker may be disabled by placing jumper JP6 on the encoder board in
position “B”.
WARNING
The output stage of the audio output consists of a 600 Ω transformer. The size of the
transformer will not allow any appreciable DC current to be passed through it
without saturation or overheating. DO NOT use the audio output to directly
modulate a DC-remote interface!
Table 13 shows the wiring of the audio section for a typical microphone-replacement
application. If an auxiliary audio input bus is available then the audio output should be
connected to it instead. These connections are not applicable if the simul-select is enabled via
programming.