User's Manual

Jotron AS| TR7750C: Operators Manual  Installation
Page 4-7
P/N: 84748 (G)
 Line input, transmitter: This is the transmitter audio line input. This signal is usually
connected to a VCS system or a remote control that uses a 600 ohm line interface.
Menu path:
TX config ►
Parameter
Range
Default
Details
Audio
(TX)
Input source
Auto | Line | Mic
| modgen | VoIP
Auto
The input source determines where the audio
is applied to the transmitter.
 Auto: Uses line input for when a
key signal is detected on one of
the remote connectors and mic
input if the key signal is detected
on the front panel connector.
 Line: Uses the 600 ohm line
interface as the audio source
 Mic: Uses the microphone input as
the audio source
 Modgen: Uses the internal
modgen as audio input source – se
also Modgen frequency
 VoIP: Uses the IP interface as the
audio source (availability depends
on radio specifications).
Audio
(TX)
Line sensitivity
-40 – 0 dBm
1 dB steps
-17 dBm
Set the sensitivity of the 600 ohm line input.
This setting determines where the VOGAD
(automatic gain control) start to operate.
Thus if it is set to -17 dBm, levels above -17
dBm will be modulated with 85% (default
setting).
For levels below -17 dBm the modulation will
decrease linearly.
Audio
(TX)
Line termination
OFF | 600 ohm
600 ohm
Set the termination of the input line to either
OFF or 600 ohm. Normally this is set to 600
ohm, but can be set to OFF on one of the
radios, if two transmitters are connected in
parallel. This is to maintain the 600 ohm
impedance on the lines.
Audio
(TX)
Line mute level
OFF or
-40 to -10dBm
1 dB steps
OFF
Below this level, the line input will be muted.
Used where noisy lines are connected to the
transmitter to avoid unnecessary noise on
the produced RF signal during periods of
silence (Automatic transmissions; VOLMET,
ATIS)
Keying
(TX)
Source
Mic, line, txkey,
txgnd, inband
Mic, txkey
Determines what signal that will be used as
the source for keying the transmitter.
Any combinations can be set
 Mic: Local PTT input from a
microphone, where the PTT is
connected to pin 4 and 8(gnd) on
the Mic/headset connector.
 Line: Keying from a phantom
signal on the line input. Pin 3 and 6
on the Rem/TR connector.
 Txkey: The transmitter is keyed by
an external voltage on the
TXKEY_P and TXKEY_N input
pins. Signals located on Pin 7 and
8 on the | connector.
 Txgnd: The transmitter is keyed by
a signal on the TXKEY_G input pin
Signals are located on Pin 4 and 8
(gnd) on the REM/TR connector.
 Inband: The transmitter is keyed
using an inband tone (see also
inband frequency and inband
sensitivity)