AT&T BELL 540 Series Common Installation And Maintenance Information

BELL SYSTEM PRACTICES
AT&TCo Standard
COMMON INSTALLATION AND MAINTENANCE INFORMATION
I.
GENERAL
This section contains common installation
1.01
and maintenance information on 4- and
6-button key telephone sets.
This section is reissued to:
1.02
Add information on 51A lamp retainer
•
(D-180557 Kit of Parts) for early 636-type
keys
Add information on KS-20419L1 buzzer now
•
provided from the factory in certain 565-
and 2565-type telephone sets
Add MD information, Table A
•
When installing or repairing any telephone
1.03
set, all
tightness in order to prevent trouble reports.
2. INSTALLATION
Keys
The 636-type key (Fig. 1) has a terminal
2.01
board arrangement to accommodate matching
cord terminal wafers, so that any line connected
to the set can be interchanged readily to appear
on any five line pickup keys.
for terminal designations on the 636A and 636B,
respectively.
Lamps associated with the buttons may have
2.02
common or individual grounds. See sections
covering connections of individual telephone sets
for lamp connections.
Certain pickup buttons on 4- and 6-button
2.03
sets are arranged for conversion to signaling.
To convert, remove P-12A892 screw detail (Fig. 1)
and make necessary wiring changes.
shows key and associated telephone sets with
convertible buttons.
BSP 502-500-120-i03_1974-11-0l. jpg Scanned by Frank Harrell, (Cowboy Frank) Castle Rock, Colorado Feb 02, 2012 18:56:54
540, 560, 1560, AND 2560 SERIES
connections should be checked for
See Fig. 2 and 3
@
American Telephone and Telegraph Company, 197 4
TELEPHONE SETS
Unused buttons, either round or square
2.04
style, may be blocked with a P-12A858
blocking ring. Insert as shown in Fig. 4.
•Lamp Retainer
In early telephone sets equipped with a 636A
2.05
or B key, the 51A lamp contact springs are
suceptible to loosing their tension.
840362347 lamp retainer (Fig. 5) is available and
can be installed between the spring contacts of
the lamps. The retainer must be ordered separately
as D-180557 Kit of Parts
Exclusion Switch Assembly
Note:
the A25B connector cable must be used.
The 565- and 1565-type telephone sets
2.06
manufactured prior to May 1967 provided
Table A an exclusion plunger in the housing.
components of the exclusion assembly were part
of a D-179935 Kit of Parts. Current manufactured
Printed in U.S.A.
SECTION 502-500-120
Issue 3, November 1974
Fig. 1-636A Key, Bottom View
.•
When exclusion feature is provided
SCREW DETAIL
An adjunct
Other
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