TM 11-6625-596-12
b. Control Settings and Operating Pushbutton Switches.
efficiency send and telephone efficiency receive
(1)
Locate the type of test to be made or the
acoustical tests should be performed on all
type of equipment to be tested in TB 11-6625-596-12/1.
telephones.
(2)
Set the front panel controls as indicated in
TB 11-6625-596-12/1 for the test selected. For example,
NOTE
to test a dynamic microphone (ME -30/U), refer to the
All tables referenced below are found m TB 11-
pertinent paragraph and table in TB 11-6625-596-12/1.
6625-596-12/1.
The front panel meter and controls are adjusted to the
positions listed in (a) below, and the pushbutton switches
a. Telephone Efficiency Send-Electrical Test.
are depressed as instructed. The pertinent table in TB
11-6625-596-12/1 gives the settings for testing
front panel controls as instructed in TB 11-6625-596-
Microphone, Dynamic ME-30/U as shown in (b) below.
12/1. The panel meter pointer should read at midscale; if
it does not, adjust the METER SENSITIVITY
(a) Preliminary control settings.
CALIBRATE, control to bring the meter pointer to the red
Control
Setting
from the hand-set.
Connect the ARTIFICIAL
MICROPHONE terminals of the TS-716/U to the
TEST CONDITION ............................. ART REC
telephone handset wires that have been removed from
NOISE GENERATOR ...........................DRIVER
the transmitter.
Connect
the
ARTIFICIAL
MICROPHONES OTHER TYPES .....Depressed
RECEIVER terminals of the TS-716/U to the telephone
handset wires removed from the receiver. Connect TEL
(b) Specific control settings.
LINE terminals L1 and L2 to the corresponding terminals
on the telephone handset. The first step of the test is to
Control
Setting
depress the LONG LINE button. Good panel meter
MICROPHONE LOAD .................................. 160
indications for various telephone units are listed in the
LEVEL A control ............................................. 20
pertinent table. The second step is to reset the TEST
LEVEL B control ............................................... 4
CONDITION switch to ART REC. The VALUE C control
VALUE C control ............................................ 12
is reset as listed in the pertinent table for this new setting
VALUE D control ............................................ 16
of the TEST CONDITION switch. Depress the LONG
LINE button.
Good scale readings for the same
NOTES
telephone units are listed in the pertinent table. Perform
1. The other columns in TB 11-6625 596-12/1
give what are considered good scale
readings for this microphone in each of the
b. Telephone Efficiency Receive-Electrical Test.
front panel controls as listed in TB 11-6625-596-12/1.
2. When the test procedure does not specify a
The panel meter pointer should read at midscale; if it
setting for one or more of the controls, these
does not, adjust the METER SENSITIVITY control to
controls are assumed to be in the positions
bring the meter pointer to the red midscale line. Remove
given for them under the starting procedure
the receiver from the telephone handset. The transmitter
should be left connected to the handset. Connect the
ARTIFICIAL RECEIVE terminals of the TS-716/U to the
(3) Pushbutton switch operation is explained in
telephone handset wires that have been removed from
the receiver. Connect TEL LINE terminals L1 and L2 to
the corresponding \parterminal on the telephone set.
2-11. Efficiency Tests of Complete Telephone Sets
To test, depress the LONG LINE button. Good scale
This group of four tests checks the sending and
readings are given in the pertinent table in TB 11-6625-
receiving efficiency of telephone sets. Telephone
2-8