TM 11-6625-1668-12
3-7. Generator Operating Procedure
The operating procedure for the generator is presented with a description of the many operating modes and
types of output signals. In order to familiarize the operator with the numerous controls and switches, examples
have been prepared of the various operating modes, listing the positions of all switches, and conditions
required to perform these operations.
a. Generator SG-860/GGM-15(V) Preliminary Starting Procedure. Perform the preliminary starting
procedures listed below before attempting to use the AN/GGM-15(V) operate only those panel controls that are
listed. Do not apply power to unused units.
(1) Check power and interface cable connections (fig. 2-9).
(2) Connect the generator to the correct ac power source (para 2-7).
(3) For a preliminary test of the generator set the controls as follows:
Control
Position
Control
Position
PWR .......................................................
OFF
MESSAGE SELECT switch .......................
M
P-N switch ...............................................
N (neutral)
CODE LEVEL switch.................................
5
DISTORTION SELECT switch .................
No DIST
CHARACTER LENGTH switch ..................
8
PERCENT DISTORTION switches ...........
0-0
CHARACTER RELEASE switch ................
FREE RUN
SELECTED CHARACTER BITS
1 to M
SINGLE switch .........................................
Not used
switches............................................
2 to M
OSC switch...............................................
INT
3 to S
ALARM switch ..........................................
DISABLE
4 to S
BAUD RATE switch...................................
75
5 to S
NOTE
The position of unmentioned controls will not affect operation in this mode.
(a) Connect adapter 1A3P3 to 1A3J3
(b) Connect a patch cord from the DRY CONTACTS output jack to the external neutral loop. The
connections to the Loop Battery Supply are illustrated in figure 3-5.
(c) Connect a patch cord from the equipment under test to the neutral loop as illustrated.
(d) Set the generator and power supply POWER switches to ON and adjust the loop current to 60
milliamperes.
(e) Set the MESSAGE SELECT switch to SELECTED CHARACTER BITS.
(f) The generator will transmit the letter A repetitively.
(g) The SIGNAL indicator lamp illuminates each time the output signal is marking. (The SIGNAL
indicator lamp requires at least 50 volts to illuminate.)
b. Generator Modes of Operation (Selected Character Bits).
(1) Synchronous. The generator will produce a synchronous pattern when the CHARACTER LENGTH
switch is set to SYNC. With the CHARACTER LENGTH switch in the SYNC position the start and stop pulses
are deleted. The SELECTED CHARACTER BITS switches are used to generate a repetitive 5, 6, 7 or 8
element synchronous pattern.
(2) Start-stop. The generator will transmit a Start-Stop character consisting of 5, 6, 7 or 8 bit lengths by
setting the MESSAGE SELECT SWITCH to the SELECTED CHARACTER BITS position and the CODE
LEVEL switch to the desired setting. To select a particular character for a five-level code the SELECTED
CHARACTER BITS switches 1 through 5 are set to mark or space in accordance with the alphabetic character
desired. (See Baudot alphabet or ASCII code in figure 3-6). The CODE LEVEL switch is placed in position 5.
The above settings will produce a five-level code consisting of five information bits plus a start and a stop pulse
or a character length of 7. Thus, with the CODE LEVEL switch in position 5 and the CHARACTER LENGTH
switch at 7, the generator will produce an undistorted character of seven equal bits in width. If the CODE
LEVEL switch is moved to position 6 and the CHARACTER LENGTH switch is moved to 8, an undistorted
character will now consist of six information bits plus a start and a stop bit (a total of 8 bits) all of equal widths.
However, if the CODE .LEVEL switch remains at 6 and the CHARACTER LENGTH switch is moved to 7, the
generator
3-8