Test Code Functions; General; Test Channels; Modulation Modes - E.F. Johnson LTR-Net 7243 Service Manual

7.5vdc 1 and 4 watts part no. 242-7243-xxx
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5.16 TEST CODE FUNCTIONS

5.16.1 GENERAL

When the special test operating code has been
loaded as described in Section 5.2.3, various test chan-
nels and test functions can be selected. The functions
selected by the various keys and the section in which
they are described are as follows:
Key
Function (See Section)
SYS
Channel select mode (5.16.2)
GRP
Modulation select mode (5.16.3)
FCN SYS
RF power toggle (5.16.4)
FCN GRP
Wide/Narrow band select (5.16.4)
FCN 1
Microphone mute (5.16.4)
FCN 4
Carrier squelch (5.16.4)
Red Butto
n Parameter Edit Mode (5.16.5)
Table 5-1 Test Channels
Channel
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

5.16.2 TEST CHANNELS

Up to 17 test channels can be selected. To select
the channel select mode, press the SYS key and then
press the "*" key to increase the channel number and
the "#" key to decrease the channel number. The
selected channel frequency is indicated by the left-
Tx/Rx Freq.
(MHz)
430.0125
432.5375
435.1125
437.5375
440.0125
442.5375
445.1125
447.5375
450.0125
452.5375
455.1125
457.5375
460.0125
462.5375
465.1125
467.5375
469.9875
most six characters of the display (the right digit indi-
cates the group number as described in the next
section). The last selected channel is saved at power
down. The test channels are listed in Table 5-1.

5.16.3 MODULATION MODES

Up to seven different subaudible modulation
signals can be selected. To select the modulation select
mode, press the GRP key. The selected modulation
signal is indicated by the group number displayed as
the right-most digit in the display. Press the "*" key to
increase the group number and the "#" key to decrease
the group number.
The last selected group is saved at power down,
and the DCS/CTCSS schemes of Groups 4-7 are also
active in the receive mode. The modulation signals
selected by Groups 1-7 are as follows:
Group
Modulation Signal
1
No transmit subaudible modulation
2
134 Hz square wave
3
Tx data filter bypassed, 134 Hz square wave
4
DCS (Digital Call Guard squelch) 023 code
5
CTCSS (Tone CG squelch) 67.0 Hz code
6
CTCSS (Tone CG squelch) 100.0 Hz code
7
CTCSS (Tone CG squelch) 210.7 Hz code

5.16.4 MISCELLANEOUS FUNCTIONS

The following functions can be selected by
pressing the FCN key and then another key:
FCN SYS - Toggles RF output power. Low power is
indicated by the " L " icon in the display.
FCN GRP - Toggles receive IF bandwidth. Narrow
band is indicated by " C " in the display.
FCN 1 - Toggles microphone mute. The microphone
is muted when
is indicated in the display.
FCN 4 - Selects carrier controlled squelch regardless
of the CTCSS/DCS code selected by the Group
function. This mode is indicated when
displayed.
5-10
ALIGNMENT PROCEDURE
is
November 2001
Part No. 001-7240-001

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