4
level on the scope. Readjust R39 slightly to further reduce signal level. Recheck R38 then R39. Notch will be
approximately 58 dB deep.
Microphone Sensitivity - R75 controls the microphone audio level into the transmit compression circuit and
therefore acts as a sensitivity control. This potentiometer has been factory set to provide adequate compression for
normal voice audio with a relatively quiet background noise level.
Jumper Settings
The TR series circuit board has 9 "Dot" jumpers. These jumpers are "in" if there is a solder short across it and
"out" if there is not. Table 1 lists the jumpers by number and explains their function. Factory settings are underlined.
Table 1
Dip Switch Settings
Table 2 describes the functions provided by the dip switch on the bottom of the unit. The factory setting are
underlined.
Table 2
Switch #
ON
OFF
1
600 ohm termination
5000 ohm termination
2
TR 10 (Does not affect TR30 or TR40)
TR20 (Does not affect TR30 or TR40)
3
TR30 or TR40
TR10 or TR20
4
TR20
TR10, TR30 or TR40
5
Allows volume to be turned down
completely.
Prevents volume from being turned down
completely.
6
TR20, TR30 or TR40 - SPKR always ON
TR10 - SPKR mute with handset off-hook
7
Locks up function tone (0 dBm)
Normal operation
8
Disables tone attenuation (All tones at +10
dBM)
Normal operation
JP#
IN
OUT
1
For 2 wire operation.
For 4 Wire or FD operation.
2
For 4 Wire or FD operation.
For 2 wire operation.
3
For 2 wire operation.
For 4 Wire or FD operation.
4
For FD operation.
For Non-FD operation.
5
For FD operation.
For Non-FD operation.
6
Normal boom/panel mic gain.
Increased boom/panel mic gain.
7
Three to ten frequency models.
One and two frequency models.
8
Three to ten frequency models.
One and two frequency models.
9
Three to ten frequency models.
One and two frequency models.
