Bell System Practices 851 Identification, Installation, Connections, And Maintenance page 8

SECTION 503-601-101
CABLE
CLAMP
KS-20419LI
BUZZER
Fig. 13-KS-20419l1 Buzzer Mounted on 851-Type
Telephone Set
circuits. One polarity guard circuit is
required for each line which is conferenceable
by multibutton depression. The polarity
guard is located between the station side
of the line circuit and the station cut-down
field.
3.19
Install H4DB handset cord in later production
models of 851- and 2851-type telephone sets
by inserting the end of the cord having the tapered
plug into the handset and the square end into jack
on bottom of set. Spring locking tab should face
away from wall at bottom of set (Fig. 19).
Warning: Cord must be removed from
jack in bottom of set anytime chassis
assembly must be put in lowered
position.
3.20
When installing H4DU handset cord in 851BM,
851CM, 2851BM, or 2851CM telephone sets,
either end of cord will fit in telephone set base
or handset. The cord should be inserted in the
jack until cord retaining clip locks in place.
Page 8
3.21
Where conditions warrant, the G3A6, G12A,
or G15A handset supplied with these sets
can be replaced with other types as follows:
• For impaired hearing-G6-type
• For weak speech-G7-type
• For noisy location-G8-type or D-180413.
Note: Refer to Section 501-211-102 for
connections of these handsets. An H4CJ or
equivalent handset cord must be used on
nonmodular type handsets.
3.22
Installation of Spade-Tipped Handset
Cords in Early Production Sets
Equipped With G12A Handset (Fig. 14):
To install spade-tipped handset cord (H4CJ or
equivalent) remove J hook stayband from the cord.
Cut back and remove cord sheath to stayband
marks. Thread spade-tipped conductors through
plug, ordered separately, (spade tips must be bent
to clear cord entrance). Pull cord until about
1/4-inch of cord sheath is in the central cavity of
the plug. Separate the conductors into two groups
and tie an overhand knot, pulling the knot to the
cord sheath. Pull cord from plug until strain relief
position is attained by knot entering sheath and
resting against plug. Feed spade-tipped conductors
straight through jack and connect to proper terminals.
Insert plug in jack.
3.23
Installation of Spade-Tipped Handset
Cords in 851BM, 851CM, 2851BM,
and 2851 CM Telephone Sets: To install
spade-tipped handset cord (H4CJ or equivalent)
insert J hook stayband of cord in slot provided in
base of telephone set and terminate on appropriate
network terminals (Fig. 26, 27, 28, or 29).
3.24
To install housing.
(1) Refer to paragraph 5.05.
(2) If chassis assembly is in lowered position,
raise and fasten in place with two captive
screws.
(3) Install collar on key.
(4) Withdraw the two mounting screws until
they are held in the housing by their threads.