Telex SR-50, ST300, SR-400 User Manual
Telex
Op er at ing In struc tions
ST300
Transmitter
SR-400
17 Channel Receiver
SR-50
Single Channel Receiver
INTRODUCTION
WHAT IS THE TELEX SOUND
ENHANCEMENT SYSTEM?
Trans mit ter: The trans mit ter gen er ates and am pli -
fies a RF (Ra dio Fre quency) car rier sig nal, mod u lates this car rier with the mi cro phone sig nal, and
ra di ates the mod u lated RF car rier.
Re ceiver: The FM VHF re ceiver is tuned to the fre quency of the trans mit ter. The re ceiver picks up the
ra di ated RF sig nal from the trans mit ter through the
an tenna and con verts the RF sig nal into au dio volt ages for use with an ear phone, head phone, but ton
re ceiver, neckloop, etc. The re ceiver fre quency must
be matched to the trans mit ter fre quency.
ANT.
WHAT FREQUENCY BAND DOES THE
TELEX SYSTEM OPERATE IN?
The Telex Sys tems fea ture a syn the sized trans mit ter
and sin gle chan nel or syn the sized re ceiv ers op er at ing in the VHF Band be tween 72-76 MHz. See Ta ble 1 for stan dard fre quen cies avail able.
Each trans mit ter chan nel can be uti lized by any
num ber of re ceiv ers in any given area. Up to eight
si mul ta neous sys tems can be used, and with proper
place ment of ad ja cent chan nels, up to ten sys tems
can be used.
ANT.
SOUND
SOURCE
RF CARRIER
SIGNAL
TRANSMITTER
Fig ure 1
Block Di a gram of Typ i cal Sound En hance ment Sys tem
FM
RECEIVER
EARPHONE
-1-
OFTEN ASKED QUESTIONS
Ques tion: Can more than one sys tem be used si -
mul ta neously?
An swer: Yes but never on the same fre quency.
You will need to have dif fer ent fre quen cies for ev ery re ceiver/trans mit ter com bi na tion. All trans mit ters are fac tory set for spe cific fre quen cies.
Ques tion: Is the sys tem more sen si tive in any one
par tic u lar di rec tion?
An swer: No, the trans mit ter’s an tenna ra di ates
equally in all di rec tions, but the sig nal is at ten u ated
by your body, walls or other sur round ing ob jects.
The re ceiv ing an tenna is es sen tially sen si tive in all
di rec tions as well.
When ever the sys tem is in use, the trans mit ter
should be left on to pre vent the re ceiver from pick ing up out side in ter fer ence.
AVAIL ABLE FRE QUEN CIES
CHAN NEL FREQ. in MHz
A 72.100
B 72.200
C 72.300
D 72.400
E 72.500
F 72.600
G 72.700
H 72.800
I 72.900
Ques tion: Can the re ceiver re ceive other trans mis -
sions when the trans mit ter is turned off?
An swer: Yes it can. Telex sys tems op er ate in the
VHF Band be tween 72-76 MHz. How ever, it is not
sus cep ti ble to ra dio wave skip, CB’ers or stan dard
FM ra dio trans mis sions.
The fre quency your sys tem op er ates on is com puter
se lected for least in ter fer ence, but there is no such
thing as a 100% clear chan nel all the time, any where in the U.S.A., for ever!
If the sys tem is go ing to be used in a per ma nent
fixed lo ca tion, it should op er ate in ter fer ence free un til such a time or date when some one else be gins
us ing the same fre quency.
If the sys tem is go ing to be mov ing among var i ous
lo ca tions, you may run into oc ca sional fre quency
con flicts.
J 75.500
K 75.600
L 75.700
M 75.800
N 75.900
O 74.700
P 75.300
Q 75.400
Ta ble 1
Fre quen cies Avail able
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TECHNICAL INFORMATION
SR-50 RECEIVER
GENERAL DESCRIPTION SR-50
The Telex SR-50 Re ceiver is a com po nent of a sys tem which op er ates on 17 fac tory pre set chan nels in
the 72 to 76 MHz fre quency band. The re ceiv ers are
de signed to be used with Telex ST-300 and PST-170
trans mit ters, but they can be used with other brands
of trans mit ters in the 72 to 76 MHz band pro vided
the fre quen cies match.
OPERATING FEATURES
Vol ume OFF/ON Con trol: The thumbwheel con -
trol serves as both an off/on switch and as a vol ume
con trol.
HEADPHONE JACK
R
Telex
A
CHANNEL
The re ceiver is turned off when the con trol is in the
ex treme coun ter clock wise po si tion, when viewed
from the rear and the vol ume is loud est when the
con trol is in the ex treme clock wise po si tion.
Head phone Jack: The re ceiver jack ac cepts a
0.140-inch (3.5 mm) di am e ter min ia ture phone plug.
A va ri ety of ac ces sory units can be plugged into the
jack for re cep tion of the de sired chan nels be ing
trans mit ted.
Belt Clip: The belt clip sup plied is de tach able by
spread ing the wire apart at the tops and re mov ing
one side of the clip form the case and then the other.
VOLUME OFF/ON CONTROL
BELT CLIP
BELT CLIPBELT CLIPBELT CLIP
BATTERY
ORIENTATION
BATTERY COMPARTMENT COVER
Fig ure 2
Op er at ing Fea tures SR-50
-3-
SPEC I FI CA TIONS
SR-50 Sin gle Chan nel Re ceiver
Tem per a ture Range .....................................................................................................0 to +50 de grees C
Sup ply Volt age ...............................................................................................2-3 Volts, (2) AA Bat teries
Bat tery Life ..............................................................................................................20-30 Hrs - Al ka line
8-10 Hrs - Nicad
Sen si tiv ity (12 dB SINAD @ 25 kHz de vi a tion) ...................................0.5µ V typ i cal/1µ V max i mum
Dis tor tion ...............................................................................................................................less than 2%
Fre quency Re sponse - 100 Hz-10 kHz .............................................................Less than 3 dB Vari a tion
Au dio Out put @ 10% Dis tor tion
Bat tery In put
Volt age
8 ohm
32 ohm
2.0V
15 mW
10 mW
3.0V
80 mW
50 mW
Con trols and Con nec tions ................................................................................Vol ume OFF/ON Switch,
Au dio Out put Jack
SR-400 SYNTHESIZED
RECEIVER
General Description SR-400
The Telex SR-400 Re ceiver is a com po nent of a
sys tem which op er ates on sev en teen user selectable
chan nels in the 72 to 76 MHz fre quency band. The
re ceiv ers are de signed to be used with the Telex
ST-300 and PST-170 Trans mit ters.
Operating Features
Vol ume OFF/ON Con trol: This thumbwheel con -
trol serves as both an off/on switch and as a vol ume
con trol. The re ceiver is turned off when the con trol
is in the ex treme coun ter-clock wise po si tion, when
viewed from the rear, and the vol ume is loud est
when the con trol is in the ex treme clock wise po si tion.
Tre ble Con trol: A push but ton tre ble con trol is pro vided to en hance higher fre quency au dio when the
but ton is en gaged, in di cated by .
Head phone Jack: The re ceiver jack ac cepts a
0.140-inch (3.5 mm) di am e ter min ia ture plug. A va ri ety of ac ces sory units can be plugged into this jack
for lis ten ing.
Belt Clip: The belt clip sup plied is de tach able by
spread ing the wire apart at the tops and re mov ing
one side of the clip form the case and then the other.
NOTE: A head phone or other de vice must be
plugged in the head phone jack in or der to turn on
the SR-400. This is to pre vent drain ing the bat ter ies
if the switch is ac ci dently left on.
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HEADPHONE JACK
SET
SWITCH
BUTTON
BELT CLIP
TREBLE CONTROL
SET
P/N:71166000
E.D.R.
VOLUME OFF/ON CONTROL
Telex
FCC ID: B5DE405
SR-400
S/N:00001
BATTERY
COMPARTMENT
Fig ure 3
Op er at ing Fea tures SR-400
SPEC I FI CA TIONS
SR-400 17 Chan nel Syn the sized Re ceiver
Tem per a ture Range .....................................................................................................0 to +50 de grees C
Sup ply Volt age ...............................................................................................2-3 Volts, (2) AA Bat teries
Bat tery Life ..............................................................................................................16-20 Hrs - Al ka line
12-16 Hrs - Nickel Metal Hy dride
8-10 Hrs - Nickel-cad mium
Fre quency Re sponse ....................................................................................................100-10 kHz ±3 dB
Sen si tiv ity (12 dB SINAD @ 74 MHz)...................................................................................1µ V max.
Dis tor tion ...............................................................................................................................less than 2%
Au dio Out put @ 10% Dis tor tion
Bat tery In put
Volt age
2.0 V
3.0 V
15 mW
80 mW
32 ohm8 ohm
10 mW
50 mW
Con trols and Con nec tions.................................................................................Vol ume OFF/ON Switch;
Tre ble Con trol Switch; Chan nel Se lec tion Switch
Au dio Out put Jack
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