AT&T Bell System KS-20449 Installation And Maintenance

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BELL SYSTEM PRACTICES
AT&TCo Standard
SECTION 024-174-200
Issue 2, December 1972
KS-20449 AMPLIFIER
INSTALLATION, CONNECTIONS,
AND MAINTENANCE
1. GENERAL
This section covers the installation, connections,
and maintenance of the KS-20449 Ll amplifier.
1.02
This section is reissued to:
• Incorporate material from Section 024-17 4-400
which is canceled
• Add an installation test for the amplifier
• Delete the schematic diagram and add it to
Section 024-17 4-500.
This section does not affect the Equipment Test
List. Since this reissue is a general revision, arrows
ordinarily used to indicate changes have been
omitted.
2. INSTALLATION AND CONNECTIONS
2.01
The KS-20449 Ll amplifier (Fig. 1 and 2)
may be installed on a 23-inch relay rack
using a 189A mounting plate drilled for mounting
the KS-20449 Ll amplifier, or may be mounted
vertically on rails similar to the mounting used
for the KS-16754 amplifier. The modified 189A
mounting plate will accommodate three amplifiers.
2.02
External connections and internal strapping
to the amplifier should be made to TBl,
located on the rear of the amplifier, as shown in
Fig. 3.
2.03
The amplifier may be operated from either
a 24- or 48-volt positive or negative grounded
power supply.
3. TEST AND ADJUSTMENTS
3.01
Test the KS-20449 amplifier with a signal
applied to the input. (For example, dialing
the central office milliwatt supply test line.) Monitor
Fig. 1-KS-20449 Amplifier-front View with Cover
Removed
the incoming line with a test receiver. The signal
level should be comparable to that in the receiver
of a telephone set.
3.02
Using a KS-6854 screwdriver, or equivalent,
turn gain control (Fig. 1) completely
counterclockwise to obtain minimum gain.
3.03
Turn gain control clockwise until maximum
loudness is reached or up to a point just
before crosstalk is heard. If the amplifier tends
to howl when a telephone transmitter is connected
to the line, reduce the amplifier gain until howling
is eliminated .
©
American Telephone and Telegraph Company, 1972
Printed in U.S.A.
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