BELL SYSTEM PRACTICES
AT&TCo Standard
SECTION 502-500-120
Issue 3, November 1974
TELEPHONE SETS
540, 560, 1560, AND 2560 SERIES
COMMON INSTALLATION AND MAINTENANCE INFORMATION
I.
GENERAL
1.01
This section contains common installation
and maintenance information on 4- and
6-button key telephone sets.
1.02
This section is reissued to:
•
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
1.03
When installing or repairing any telephone
set,
all
connections should be checked for
tightness in order to prevent trouble reports.
2.
INSTALLATION
Keys
2.01
The 636-type key (Fig. 1) has a terminal
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. See Fig. 2 and 3
for terminal designations on the 636A and 636B,
respectively.
2.02
Lamps associated with the buttons may have
common or individual grounds. See sections
covering connections of individual telephone sets
for lamp connections.
2.03
Certain pickup buttons on 4- and 6-button
sets are arranged for conversion to signaling.
To convert, remove P-12A892 screw detail (Fig. 1)
and make necessary wiring changes. Table A
shows key and associated telephone sets with
convertible buttons.
P·I2A892
SCREW DETAIL
Fig. 1-636A Key, Bottom View
2.04
Unused buttons, either round or square
style, may be blocked with a P-12A858
blocking ring. Insert as shown in Fig. 4.
•Lamp Retainer
2.05
In early telephone sets equipped with a 636A
or B key, the 51A lamp contact springs are
suceptible to loosing their tension. An adjunct
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:
When exclusion feature is provided
the A25B connector cable must be used.
2.06
The 565- and 1565-type telephone sets
manufactured prior to May 1967 provided
an exclusion plunger in the housing. Other
components of the exclusion assembly were part
of a D-179935 Kit of Parts. Current manufactured
@
American Telephone and Telegraph Company, 197 4
Printed in U.S.A.
Page
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BSP
502-500-120-i03_1974-11-0l.jpg Scanned by Frank Harrell, (Cowboy Frank) Castle Rock, Colorado Feb 02, 2012 18:56:54
