A D J U S T M E N T O F T H E T R A N S M I S S I O N L E V E - Philips SPENDEX 40 Maintenance Manual
Speech encryption decryption equipment
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Also See for SPENDEX 40:
- Operating manual (25 pages) ,
- Operating instructions manual (21 pages)
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NATO CONFIDENTIAL
S P E N D E X 4 0 U A 8 2 5 1 / 0 0 A N D / O l L I M I T E D M A I N T E N A N C E M A N U A L
• " X 6 9 a n d X 7 2 a r e f i x e d o n t h e b o t t o m o f t h e p o w e r s u p p l y c o m p a r t m e n t
(see Fig. 7.3);
- Place the mounting strip and fix the connectors with the
appropriate M2.5 screws;
- Put the power supply unit into the apparatus. See to it that the
various connections do not get jammed;
- Tighten the 12 captive M4 socket head screws.
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7 . 5 A d j u s t m e n t o f t h e t r a n s m i s s i o n l e v e l
With the potentiometers R18 and R19 on the line interface board the
transmission level can be accurately adjusted. R19 is used for
adjusting the level with the internal modem off line (microphone
signal/dialling tones level, factory setting -15 dB) and R18 for
adjusting the level with the internal modem on line (modem signal
level, factory setting -19 dB with equipment type UA 8251/00 and
-12 dB with equipment type UA 8251/01). The limits within which the
modem signal level can be adjusted depends on the transmission level
setting of the modem.
7 . 5 . 1 A d j u s t m e n t o f t h e m i c r o p h o n e s i g n a l / d i a l l i n g t o n e s l e v e l
- Loosen the 14 captive M4 socket head screws, with which the
m a i n s / l i n e fi l t e r i s fi x e d i n t h e a p p a r a t u s ;
- Take the mains/line filter carefully out of the apparatus. See to
it that the connections with the line interface board do not come
loose;
- S w i t c h o n t h e e q u i p m e n t a n d w a i t u n t i l " * " a p p e a r s i n t h e
d i s p l a y ;
- Set the equipment on Tone Dialling, Low Frequency, 4-wire and Full
Duplex (TDLF4WFD);
- Bring the apparatus in the test state. The display shows
"TESTMODE";
- Connect the line connecting cable and insert a resistor of 600 Q
between the pins "EB" and "GND" of the telephone connector;
- Key in test code 1. The display shows "KBD TEST";
- Press key 2. The display shows "22222222" and a tone is audible;
- Go off hook;
- Connect the pins "EB" (+) and "GND" (-) of the telephone connector
to a multimeter and adjust the desired level value with
potentiometer R19;
- Press P key. The display shows "TESTMODE";
- G o o n / o f f h o o k . T h e d i s p l a y s h o w s " * " ;
- Switch off the equipment;
- Replace the mains/line filter into the apparatus. See to it that
the connections with the line interface board do not get jammed.
Then tighten again the 14 captive socket head screws.
7 . 5 . 2 A d j u s tm e n t o f th e m o d e m s i g n a l l e v e l
- Loosen the 14 captive M4 socket head screws, with which the
9 9 2 2
1 5 4
1 3 4 3 1
7 - 1 0
NATO CONFIDENTIAL
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