Bell 851 Series Guide

BELL SYSTEM PRACTICES
AT&TCo Standard SECTION 503-601-101
Issue 5, December 1973
TELEPHONE SETS-851- AND 2851-TYPE
IDENTIFICATION, INSTALLATION, CONNECTIONS, AND MAINTENANCE
1. GENERAL
;~ 1.01 This section is reissued to:
o Show 851BT-* and 2851BT-* telephone sets
rated MD and replaced by 851B and 2851B
telephone sets, respectively
e Show 851BT and 2851BT telephone set bases
rated MD and replaced by 851BM and 2851BM
telephone set bases, respectively
e Show lA housing rated MD and replaced
by 851A housing
o Show G 12A handset replaced by G3A6 handset
e Include information on 4-type speakerphone
e Revise Table A
1.02 The 851AlM, BlM, •BT• and 2851AlM, BlM,
•BT• telephone sets are rated MD.
2. IDENTIFICATION
2.10 The
851- (rotary dial) and 2851- (TOUCH-TONE®
dial) type sets are available completely
assembled. Their basic modules are also available.
2.02 Pu1pose: Provides features of a 6-button
key station (5-line pickup and hold)
at wall
installations.
2.03 Application: Used with central office or
PBX line circuits in lA, lAl, 1A2, or 6A
Key Telephone Systems. Both the 851-type and
2851-type
sets are wired for lAl, 1A2, and 6A
systems. For lA Key Telephone System, internal
wiring changes must
be made.
2.04 01·del'ing Guide:
Note: The 851- and 2851-type telephone sets
can be ordered completely assembled (851B-'
or 2851B- •, Fig. 6 and 7) or modular (851BM
or 2851BM, Fig. 3 or 4) telephone set bases.
Fig. 1-851-Type Telephone Set Base
Fig. 2-2851-Type Telephone Set Base
0) Amet·ican Telephone and Telegraph Company 1973
Printed in U.S.A. Page 1
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SECTION 503-601-101
/
(
I
I
I
851A
FACEPLATE
I
I ~~~ ··~·~ .•
~lJS
2851A
FACEPLATE
/
/
G3A6
HANDSET
Fig. 3_.Station Modular Arrangement, 8518 and 28518 Telephone Set Showing Current 851A Housing and
Baseplate<!
Page 2
MP rrmrrnrrrrr:mrrr rnrrnr ram,,
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85JA HOUSING
/
('
I
I
I
/
/
851A
FACEPLATE
2851A
FACEPLATE
ISS 5, SECTION 503-601-101
8518T
TELEPHONE
SET
BASE
I
~~~--
H408 ~ /',
CORD ~/ ,
21J\ •!'
TAPERED ENO OF CORO
Gl2A
HANDSET
Fig. 4--$Station Modular Arrangement, Early Production 851- and 2851-Type Telephone Set Showing Current
851A Housing and Baseplate(!
Page 3
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~ 503-601-101
If the telephone set base is ordered, the
remaining coded apparatus must be ordered
separately and installed to furnish a complete
S51B-* or 2S51B-* telephone set (Fig. 6 and 7).
'Complete code by adding color suffix from
Table
A.
TABLE A
COLOR ORDERING GUIDE
HOUSING, CORDS
COORDINATED
AND HANDSET
FACEPLATE
COLOR
SUFFIX
COLOR
SUFFIX
Black
-03
Charcoal
-70
Ivory
-50
Muted Ivory
·-80
Green
-51
Light Green
-71
Red
-53
Muted Red
-69
Yellow
-56
Light Yellow
-72
White
-58
Light Gray
-73
Light Beige
-60
Muted Beige
-75
Aqua Blue
-62
Muted Blue
-76
(a) Telephone Sets:
i>Set, Telephone, S51B- •-Completely assembled
set consisting of an S51BM telephone set base
[equipped with an SR dial (rotary), 635A5
key,
PlB ringer, KS-20419Ll buzzer, network,
quick-connect connecting blocks, and screw
type terminal field], S51A housing, S51A
faceplate, and G3A6 handset .•
Set, Telephone, 2S51B-*-Same as the S51B-*
telephone set except equipped with a 35C3A
(TOUCH-TONE dial) and 2S51A·* faceplate.
A supply of
E-5S37 Forms (key button designation
tabs)
is furnished with the sets.
(b) Modula1· Items:
o Base, Telephone Set, S51BM
e Base, Telephone Set, 2S51BM
e Housing, S51A- *
Page 4
e Faceplate:
S51A·* (S5Hype telephone set)
2S51A- * (2S51-type telephone set)
e Handset, Gl2A·• (early sets)
e Handset, G3A6-* (current sets)
e Cord, H4DB-* (early sets)
(c) Options:
e Buzzer, KS-Sl09L2 (AC or DC)
e P-21F938 Switch, Exclusion Switch Assembly
e P-90D170 Polarity Guard Assembly (for
2S5Hype telephone set)
o Diode, KS-15724Ll (station busy lamp)
e Speakerphone, 3-type:
Dial, SC
Unit, Control, 55-type
Transmitter, 666-type
Loudspeaker, 760A
Transformer, 2012B
Speakerphone, 4A:
Dial, SC
Set, Loudspeaker, lOS-Type
Transmitter, 6SO-Type
Unit, Power, S5B1·49 or
Transformer,
2012B
Adapter, 223-49
e D-1S0375 Kit of Parts (adapter cable assembly
for installations utilizing A25B connector
cable)
e Amplifier-type handsets
Handset,
G6AR (MD) or G6B
Handset, G7AR (MD) or G7B
Handset, GSA (MD) or GSB
Handset, D-180413
e Hold Lamp
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ISS 5, SECTION 503-601 .. 101
Fig. 5-*Early Version Baseplate and Housing•
(d) Replaceable Components:
e Dial, SR or 35C3A
e Ringer, PlB
e Key, 635A5
e Buzzer, KS-20419Ll
e P-23F503 Collar
e Lamp, 51A (lOV) for all keys
e All items listed as modular
2.05 Design Featu1·es:
e Sets are surface mounted on wall or vertical
surface using holes for standard outlet box
or keyhole slots.
e Handset is cradled on top, permitting on-hook
dialing when speakerphone
is furnished.
e All key buttons including hold can be
illuminated (lamps are furnished).
e All pickup buttons convertible to signaling.
e Provision made for addition of the following
optional features:
(1) Exclusion
(2) Polarity guard
(3) Buzzer, KS-8109L2
(4) Busy lamp
(5) Speakerphone
(6) Amplifier-type handsets
e An access hole is provided in the Pl-type
ringer for ringer biasing spring adjustment.
Refer to Section
501-259-101.
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SECTION 503-601-101
Fig. 6-851-Type Telephone Set, Assembled Station
3. INSTALLATION
3.01 When mounting the 851- or 2851-type
telephone set, select a location which provides
at least 6 inches of clearance on all sides to permit
removal
of the handset and for maintenance.
3.02 The telephone set should be mounted before
installing the modular items. To expose
the mounting holes, the hinged chassis assembly
must be lowered by loosening the captive screws
(Fig.
13) holding the top of the chassis. Where
desired, the chassis assembly can be removed by
springing the hinge brackets sufficiently to clear
the pins. The base pan can
be mounted directly
to the wall using the keyhole slots,
or holes are
provided
for mounting over an electrical outlet
box.
Caution: A
void damage to wall 01· telephone
set whenever chassis is in lowered position.
Page 6
· rttrTrrs:r rr ·· nnrmr rrrr trr
Fig. 7-2851-Type Telephone Set, Assembled Station
3.03 Sets can be wired using either inside wiring
cable or connector cable. When mounted
over an outlet box, bring wiring through opening
in base pan before mounting. When exposed, bring
wiring up from bottom (right side of handset cord
jack). Allow
20-22 inches of cable inside set for
routing and terminating.
3.04 With wiring brought into set, and base pan
mounted, replace chassis assembly if previously
removed,
but leave in lowered position.
3.05 Where IW cable is used, prepare and route
as follows:
r
(1) Remove sheath to surface of outlet box or
bottom of hole
in base pan, depending on
method of wiring.
(2) Remove cable clamps. Pinch legs of clamp
from front of chassis (Fig.
8).
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(3) Slip one of the clamps provided with set
around conductors approximately 9 inches
from end of sheath. Add second clamp 2 inches
above first.
(4) Form slack loop as shown in Fig. 9 or 10
and install first clamp in hole to left of cord
jack.
(5) Route cable below jack and install second
clamp
in hole to left of ringer.
(6) Twist ends of conductors together and feed
through opening between dial, ringer, and
connecting blocks.
CABLE
CLAMP
KS·20419LI
BUZZER
Fig. 8-KS-20419L1 Buzzer Mounted on 851-Type
.Telephone Set
3.06
If the set is served by the connector equipped
end of an
A25B connector cable, a D-180375
Kit of Parts must be used to obtain raw-ended
conductors for termination. The mated connector
and plug should be located as shown· in Fig. 11.
Check that connector and plug do not interfere
with operation of line switch. Cable is routed and
fastened
in same manner as IW cable (Fig. 9 and
10).
ISS 5, SECTION 503-601-101
Fig. 9-lnside Wiring Cable, Exposed Wiring
3.07 Check before terminating that sufficient
slack is provided to permit hinging action
of chassis assembly.
Cable slack must he in area behind
dial and not touching ringe1·. Chassis
cannot b~ secured if slack lies between
base pan and netwo1·k or base pa11
and c01·d jack.
3.08 Since individual terminals are not designated
on
the quick-connect blocks, a label is
provided
on the inside of the housing as a wfring
guide (Fig. 12). Terminals 1-30 are on the upper
block and
31-54 are on the lower block. Terminals
51-54
are spare. Use a 714B tool to terminate
conductors.
Page 7
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SECTION 503-601-101
Fig. 10-lnside Wiring Cable, From Outlet Box
3.09 Exclusion Switch: To provide exclusion,
install the
P-21F93S exclusion switch assembly
as follows:
(1) With chassis in lowered position, fasten
switch assembly to line switch bracket using
screw provided
in kit. Screw must be inserted
in hole from rear of bracket.
(2) Position switch assembly horizontally (Fig.
13) and fasten securely.
3.10 Polarity GuaI"d: When required with the
2S51-type telephone set, install the P-90D170
Guard Assembly as follows:
(1) Remove the 635A5 key by springing the
support brackets inward until key can be
removed from pins. It is not necessary to
disconnect the line plugs
on the rear of the key.
Page 8
Fig. 11-Connector Cable and D-180375 Kit of Parts
(2) Mount the guard assembly to the left-hand
bracket in the position shown in Fig. 14
using the screw provided with the assembly.
Screw must be inserted through hole from inside
of key support bracket.
(3) Replace key in brackets.
3.11 Speakerphone: These sets are factory-wired
for 3-type speakerphone except that the
S51-type telephone
set requires the replacement of
the
SR dial with an SC dial to provide a second
set of off-normal contacts (P3 and P4 leads). When
replacing the dial the
adapter brackets must be
removed from the
SR dial and added to the SC dial
(Fig.
16). Terminate the additional leads as shown
in
Fig. 22. With both the rotary and the
TOUCH-TONE sets, a loudspeaker and transmitter
must
be installed external to the set and wired to
the 55-type control unit. The control unit can
be
located near the telephone set (Fig. lS) or at the
KTS equipment (Fig. 19).
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Fig. 12-Connecting Block Wiring Label
Fig. 13-Excluslon Switch Installed and Hinged
Chassis Mounting Screws
3.12 If 4-type speakerphone is provided, the 223A
adapter is used to interconnect the 4-type
speakerphone system (680-type transmitter, 108-type
loudspeaker set, and the 85Bl power unit or
2012B
· transformer).
!SS 5, SECTION 503-601-101
Fig. 14-Polarity Guard Position
3.13 For connections to the 3- or 4-type
speakerphone system, refer to the appropriate
section in Division 512.
3.14 When an 851- or 2851-type telephone set is
multipled with sets furnishing speakerphone
features, certain leads must be disconnected,
insulated, and stored to avoid interference with
working circuits. The designation of leads to be
removed are as follows:
Tl, Rl, P3, P4, AG, and
LK.
3.15 Buzzel': The KS-20419Ll buzzer is mounted
on
an insulated bracket below the dial
(Fig. 8). If required, the KS-20419Ll may be
replaced by the KS-8109L2 buzzer
(14-30 volt ac
or
de) which would be mounted using both screws.
3.16
/(ey Featuz·es:
e All pickup positions of the 635A5 key are
convertible to signaling by the removal of
the P-28E773 locking pins from the positions
involved and making
the necessary wiring
changes (Table
C).
e Lamp and set wiring are provided for
illuminating all key positions, except in the
hold position
where the associated lamp
leads are insulated and stored.
e Line appearances on the key can be rearranged
by switching the color coded plugs on the
rear of the key or rearrangement of the
cross connections at the key equipment.
Page 9
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SECTION 503-601-101
3.17 Install H4DB handset cord by inserting end
of cord having
tapered plug into handset
and square end into jack on bottom of set. Spring
locking tab should face away from wall at bottom
of
set (Fig. 4).
t
Care should be taken that contact
suda'ces of plugs on cord mate with
those of handset and telephone set
jacks since the plugs can be inserted
in the reverse position.
Caution: Cord should be z·emoved from
jack in bottom of set anytime chassis
assembly must be put in lowe1·ed position.
3.18 Where conditions warrant, the G3A6 or G 12A
handset supplied with these sets can be
replaced with other types as follows:
e For impaired hearing-G6-type
e For weak speech-G7-type
e For noisy location-GS-type or D-180413
Refer to Division 501 for connections of these
handsets. When either of these handsets is used,
an H4CJ or equivalent handset cord must
be used.
3.17 Installation of Spade-Tipped Handset
Cords In Eal'/y Production Set Equipped
With G12A Handset (Fig. 17): To install
spade-tipped handset cord (H4CJ or equivalent)
remove P-376819 J Hook Stayband from the cord.
Cut back and remove cord sheath to stayband
marks. Thread spade-tipped conductors through
plug 840217590 (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 P-22F620 and
connect to proper terminals. Insert plug
in jack.
Page 10
3.20 To install housing:
(1) Refer to 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.
With both line switch plungers fully lifted, move
the housing directly into position around
the
telephone set (if an exclusion switch is installed,
the left plunger
will be felt to touch the exclusion
switch when the housing is about 3/8-inch from
the base). Depress both plungers to their
on-hook position. Continue moving the housing
into position against the base. Release plungers.
(5) Fasten housing in place with two captive
screws.
(6) Check complete operation of line switch and
exclusion feature.
3.21 Use a Form E-5002-A or E-5002-B as a
station number card for a TOUCH-TONE
station and Form E-4203-G or E-4204-G for rotary
sets.
3.22 To install faceplate:
(1) If installing 2851A faceplate (2851-type
telephone set) place station number card
in
from front of faceplate in standard manner.
(2) Insert tabs on faceplate into slots of housing.
Use a KS-16750 type releaser or equivalent
to depress the tab of the faceplate retainer
clip
while seating the faceplate. To insure proper
positioning of the retainer
clip, raise the handle
of the releaser
well above horizontal, as shown
in Fig. 15, before withdrawing the tool.
(3) If the latching characteristic of the P-269524
retainer clip is inadequate, replace with a
840155618
clip.
3.23 The 635A5 key uses a E-5837 form (key
button designation tabs).
To install, squeeze
sides of cap to remove from key button and insert
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designation tab. When replacing cap or key button
make sure assembly snaps into place.
If cap does
not snap
in place properly, rotate 90 degrees.
Fig. 15-lnstallatlon 851A Faceplate
Fig. 16-Dial Adapter Bracket
ISS 5, SECTION 503-601-101
Fig. i7-lnstalling Spade-Tipped Handset Cords in
Early Production Sets
4. CONNECTIONS
4.01 All incoming connections are made on the
quick-connect connecting blocks. Terminate
IW cable as shown
in Fig. 22 and 23, using the
label inside the housing
as a guide in locating
terminal numbers.
4.02 All leads or straps involved in service or
option
changes are equipped with spade
tips. If not factory terminated, leads are insulated
and stored.
4.03 Connection Index:
Table
B-Connections For lA KTS and/or
Station Busy Lamp
Table C--Pickup-Signal Key Conversions
Table D-Polarity Guard Connections For
2851-type Telephone Set (P-90Dl70
Guard Assembly)
Fig. 20-Exclusion Switch Connections
Fig.
21-Hold Lamp Connections
Page 11
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SECTION 503-601-101
Fig. 22-S51-Type Telephone Set, Connections
Fig. 23-2S51-Type Telephone Set, Connections
5. MAINTENANCE
5.01 Maintenance replacement should be limited
to the following:
o Complete telephone sets
• Modular items
• Optional items
o Replaceable components
5.02 When dial replacement is necessary in the
S51-type telephone set, use an SR dial for
nonspeakerphone sets and an
SC dial for sets with
speakerphone. Remove dial
by loosening mounting
screws and springing dial brackets sufficiently
to
release dial from locating pins. Left hand bracket
may have to
be moved slightly toward right side
of
set to permit dial to clear screw terminal field
(or loosen and move screw terminal field). Transfer
adapter brackets from dial being replaced
to new
dial (Fig.
16).
5.03 Maintenance of the 35C3A (TOUCH-TONE
dial) dial is not recommended and the dial
should be replaced. Adapter brackets are not
involved when replacing the TOUCH-TONE dial.
5.04 When necessary to remove housing, the
faceplate must first be removed by using a
KS-16750 type releaser or equivalent in catch in
bottom of faceplate. Housing can then be removed
by loosening two captive screws under faceplate
area.
Page 12
5.05 For field replacement of S51A housing-early
version of housing (Fig. 5) can be used with
sets equipped with either the early or current
baseplate (Fig. 3, 4, and 5). The current housing
(Fig. 3 or 4) can
be used with the current baseplate
only.
5.06 Access to the ringer is obtained by lowering
the hinged chassis assembly. The ringer
can be removed by loosening the two shouldered
mounting screws.
5.07 The current production 635-type keys have
been modified for
easy lamp replacement
by merely removing the lamp cap and inserting a
553-type tool through the hole in the top of the
button. In early production keys it was necessary
to remove faceplate, housing, key collar, and button
for lamp replacement.
760A 666-TYPE
LSPK TR MTR
R2FK
T7A OR
CD
Tl IA CD
121
(71
55-TYPE
CONTROL
UNIT
(21
2012 8
TRNSF
851· OR 2851·
TYPE
TEL SET
IW
CA
(71
TO KTS EQUIP
(SEE NOTE)
NOTE
DO
NOT TERMINATE
Tl,Rl,P3 OR IT,P4
OR lA,AG AND LK
LEADS
Fig. 18-Block Diagram, Control Unit Located Near
Station
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760 A
LSPKR
R2FK
co
(2)
44A
CONN
BLK
666-TYPE
TR MTR
IW CA
HA OR
TllA CO
(7)
851- OR 2851-
TYPE
TEL SET
6--
IW CABLE OR
CONN. CABLE
(50)
KTS
EQUIP
(7)
(9)
55-TYPE
'----=-----J CONTROL
UNIT
121
2012 B
TAN SF
Fig. 19-Block Diagram, Control Unit Located at KTS
Equipment
(Y-G)
LG~
r,
KS-20419,LI
TB
STRAP
(BL)
21
STRAP
(BL)
12
HOH:
R
A OR H
(0-WI
B (NOTE
2)
INOTE I)....-'
L..i-o
ET
41 (V-BL)
ER
41
(BL-VI
A OR H
43
(V-01
(NOTE
3l ....-'
EB
44
(0-V)
'
NOTES'
ISS 5, SECTION 503-601-101
i
7
l_!i
(V-BLI
~
l
IW-BLI
If!
l8L-V)
.?.
(BL-WI
l
(W-0)
e-
(V-0)
v
10-W)
l.Q (0-V)
VJ
/
'
n
r:
I
I
tv
lI
I
l:
PU
31
~ KEY
EXCLUSION
SWITCH
P-21F93B
l. STORED SPADE-TIPPED LEADS OF LINE TO BE EXCLUDED.
2. WHEN OTHER THAN LINE I IS EXCLUDED ON IA KTS, DISCONNECT,
INSULATE AND STORE
{0-W) LEAD FROM TERMINAL 4 CONNECT
BALANCE LEAD OF LINE INVOLVED TO TERMINAL 4.
3. FOR IAI OR IA2 KTS, CONNECT (0-W) EXCLUSION LEAD TO
TERMINAL 10. Al GROUND MUST BE SUPPLIED DIRECTLY TO
EXCLUDED STATION.
Fig. 20-Exclusion Switch Connections
HOLD LAMP
CB
(G-Y)
36
(G-Y)
"'l
(Y-G)
35
(Y·G)
BZI
TO KTS
IF HOLD LAMP OP£RATIOH IS REQUIRED; REMOVE, INSULATE, ANO STORE BUZZER LEADS.
Fig. 21-Hold Lamp Connections
Page 13
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SECTION 503-601-101
INSlOE WIRING CABLE
TO IA,IA
!AZ OR 6
KTS LIN
CIRCUIT
I,
A
E
s
TO
R-
SPEAKE
PHO
NE
~
Tl I)
R( I)
A, HORS
Al OR 8
LG
L
T(2l
R(2)
A, H ORS
B
LG
L
T(3)
R(3l
A, H OR S
B
LG
L
Tl4)
R(4)
A, H ORS
B
LG
L
T{5)
R(5l
A, HOR S
•
LG
L
SPARE
SPARE
SPARE
SPARE
821
ez
BL
SG
Bl
RI
T
R
A OR H
•
Tl
RI
P3
P4
AG
LK
lW-Bll
(BL-WI
(W-Ol
(0-W)
{W-G)
(G-Wl
(W-BR)
(BR-W)
(W-Sl
(S-W)
(R-Bll
(BL-Rl
(A-0)
(0-R)
{R-Gl
(G-Rl
IR-BRI
{BR-A}
(R-Sl
(S-RJ
{BK-BLI
(BL- BKl
(BK-0)
lO-BK)
{BK-G)
tG-BK)
{8K-8Rl
(BR-BK)
(8K-S)
IS-BKl
(Y-BL)
(BL-Y)
(Y-0)
{0-Y)
{Y-G)
(G-Y)
{Y-BRl
(BR-Yl
(Y-S)
!S-Yl
(V-BL)
(BL-V)
(V-0)
{0-Vl
(V-GJ
(G-Vl
(V-BR)
!BR-VJ
(V-Sl
{$-Vl
CONNECTING BLOCK
~
"
~
~
~ lW-Bll
1~*
(BL-W)
2
f{BL-W)*
03
[W-0)
~*
4
to-W)
5 tW-Gl
G
(G-WJ
7 (W-BR)
6 !BR-WI
9
(W-S)
10
(S-Wl
.
II
(R-Bll
12
(Bl-R)
13
(R-Ol
14 (0-Rl
15 IR-GJ
16 (G- Al
*
17 IR·BR}
18 (BR-Rl
19
IR-S)
20
{S-R!
21
{BK-BL)
22
(BL-810
" {81<-01 •
24
(<;>-BK)
25
(BK-G)
26
(G-8Kl
!
27 {BK-ORI
0
ze~'*
29
(BK-S)
30
(S-BK)
31
(Y-BL)
32 IBL-'l'l
"
33
(Y-0)
•
•
34
(0-Y)
*
35
(Y-G)
36
(G- 'i)
"
(Y-BR)
36
(BR·Y)
39 IY-Sl
40 !S-Y)
41
{V-BL)
42 {BL-Vl
43 \V-0)
44 {0-Vl
45 !V-G)
46
\G-V)
47 (V-BRJ
48 (BR-VI
49
(V-S)
50
(S-V)
,,,,A
~.
TERMINAL BOARD
635A5 KEY
(Y-G) J
IG·Yl LG
* ~______,___, L ~
(0 BK)
(SK-BU
(G-W)
I
{0-WJ
,..-,.4 !Yl
n
~
'
I
{S-W)
I
9
I I
I IG
RI
I
n
~'
(BL-SKI
y
{BK- BLl
--
-~
{BR-OK)
L
(BK-BRJ
RI
I 2 7 20
00
0 0
-"
(BL)
::0:21
t Bll
~
~"
=:"
;:;:M
IG::O:
18:::::
3
a=:
10;::
-
'
13
-"
=:11
~
3
~sr
2
I
.__,_., 3 h
r:t 4
- 5
>-----('
6
~ >-1 l
2
<ii >--1
I I
LG
~
L
I
~:]
h
f>-~5 w
~('
6 ~
I z I
I 2 ~
>--1
I o
I
1
LG
~
L
~-
f-1-' !l
h
"h'l
i--J :
G ~
>--__,
2 ~
>--1
I ' t1
G
~
L.
-·-·--
·-
~ ·~ J h
~·
~r--Hi- 5 ?=
~:
-H (> ~
2::;
i--J
'
·--+--:> l.G
OB
··-,) L
f-----"-·-
~ '1
h
f-H"
.... 1--t-:> 5 w
'--.-{'
H 6 ~ i--J I
-Hz ...1
>_t
--t~ ~G w
~
·-J-.'L
!Gl'
IBU
mu
IBKl
IR
(BR)
IY)
(V-G)
IGJ
'"
Iy)
(Y-BR)
{S-V)
p 1$7
iCKUP
2ND
PICKUP
JRO
PICKUP
'1TH
PICKUP
TO
SHEET 2
Fig. 22-851-Type Telephone Set, Connections (Sheet 1 of 2)
Page 14
nm;mrrrrrs rnrr r 1 T' ff
TCI Library: www.telephonecollectors.info

FROM
SHEET l
ISS 5, SECTION 503-601-101
(G)
(Bl<J
(Rl
l8Rl
(Y)
(V-Gl
<GI
(Y)
r--
1
l
NOTES
L cor-mECT!OtiS FOR P.8 Rl,'.GER SHOWN RINGER CONNECTIONS FOR
SETS EQUIPPED W!Tf• >'!.'. RtNGER SAME AS PIS EXCEPT ( Sl AND
( S-Rl LEADS ftR[ 1•tsuu<rrn Mm STORED ( Bll LEAD REMOVED
FROM CURRENT VOC£L PIA RINGERS
2 LINE SWITCH CPER.'..-:\:, SEQUENCE
be MAKES
dt lit.>:($
ob 9q(,\><S
19 sq£:,•·s
3 CONTACT k';'J ~E:..:,s •uRIHSHf.O ON BC DIAL ONLY.
4. CURRENT 85 9 ~E:_f?,.;O.'IE SETS ARE EQUIPPED WITH G3AG
HANDSET ""''<"' :s Y.,!R£D DIRECTLY TO THE TELEPHONE SET
EARLY PPC:J,;:-:~.•.: 851· TYPE TELEPHONE SETS WERE EQUIPPED
WITH.~ Gl2·\ ... .:. .. ::·SET USING A PLUG-ENDED CORO
H4CJ
CORD
(W)
GM6
HANDSET
{NOTE 4)
--·-::~---~ RCVR
________ J_J ;
I I
..,
RR
(RI 3
TRMTR
{Bl<l
-·----·
{W)
.-~--<_.:;;-'-~~-0-
c
_(_Y_J ____ ,_ __ _J J
(Y-8R\ L2
--',-S-~V~l'------------------~,,.AOR425E
l NETWORK
Fig. 22__,.851-Type Telephone Set, Connections (Sheet 2 of 2).
Page 15
TCI Library: www.telephonecollectors.info

SECTION 503-601-101
:;"«
INSIDE WlAlNG CABLE
CONNECTING BLOCK TERMINAL BOARD
635A5 KEY
," '~
*
(Y-G)
'1
~
~
*
{G -'I") L ¥
~
HOLO
{0-BK)
3 ~
pJ
KE)
~
{BK-BU
...
2
~(W-BLl
(G-W)
I
T(l}
(W-Bll
'.,J
01 l
<w-eu * :'
~ 'l
>---.
(BL-Wl *
..
4
A {l)
10L-W)
~··
i.
~~5
r----('
0~
~*··.·•
'.l
)-J I IS"
AH ORS
IW-0) {0-Wl
)----J PICKUP
Al ORB
to-Wl
(;)?
(0-W}
,.-,.4 {Yl I .
)-J
LG {W-Gl {W·G)
~
LG
O@
IG-Wl {G-WJ
..
L
'
>.1
T (2) lW-BA)
(W·BR)
...
>---. ..
:·
~1
R (2)
tBR-Wl
(13R·W)
I+ 5 w
)-J :
. I 6 ~ 2ND
A, HORS {W-S)
9 lW-Sl
,.
{S-W)
' : 2
~
)-J
PICKUP
B
!S-Wl 10 (S-Wl
* ;;
I
·····
I o
LG {A-BL)
T::'
{R-Bll
....
I
~
{BL-A)
12 lBL·R)
••
1
LG
L
•'/
T(3}
{R-Q}
!<:
"
lR-0)
>---.
1·~
<
"~l
R (3)
lO-Rl
14
IO·Al
...
·1
I
)-J :
t~
;.
,:
I \G-R)
6 ::: 3RO
A, H OR S (R·Gl 15 (A -Gl
2 ~
)-J
P!CKIJP
0
(G-Rl
~flJ
01£
: :~~:~)
* ><
I I
~
LG IA-BAJ
17
• LG
~
~1?~
:::
..
(BR-Al
"
taR-Rl
L
~
'
T (4)
(R·S)
,q
tR-5)
•.·•
~~1
>---.
R (4)
(S·Rl
20
tS-R)
~r
)-J :
I 6
~
'4TH
A, H
ORS
{BK-BL)
21 tBl<·BLl
~·
(BL-BK)
2::;
~
PICKUP
TO IA,IAI, B
(BL-BKJ
22
l8L-0Kl
y
(BK- BL)
I
IA2 OR GA
LG {BK-OJ
"
18K-Ol
LG
~
KTS LINE
CIRCUITS
(0-BK)
24 IO·OK)
L
'\ ~·-----·
T (51
{BK-Gl
25
{BK-G)
'
'j
>---.
...
r-+-? 4
R (5) (G-8K)
26
(G-BKl
f_;,
... i-1-'1 5 w
)-J :
I 6
:;
5TH
A, H OR S {8K-8RJ
27
(9K-BRI
~·
lBR-BKl
~ 2 ~
>-----'
PICKUP
B
(BR-BK)
26
CBR-BKJ T {BK-BR)
'
)-J
LG
{BK-S)
29
CBK-Sl
LG
00
{S-BKI
>D
lS-BKl
L
SPARE (Y-Bll
"
{Y-Bll
R)
SPARE (BL-Yl
"
{BL-Y)
* ) 2 7
{G)~
SPARE (Y-Ol
"
IY-OJ
00 0
SPARE
10-Yl
'4
IO-Yl
(Bl)
BZI (Y-G)
'5
(Y-GJ
~"
BZ
{G-Y}
'6
(G-Yl ;:21 c• lBll
BL
{Y-BRl
"
(Y-BRl
,,~
{Y-BRl
SG \BR-Yl
>B
{BR-Yl
~"
~.i
Bl {Y-Sl
'9
(Y-S)
:::::19
{BKI
RI
{S-Y)
40
{$-Y} ;:14
{R)
(V-Bl)
41 IV-BL)
16;;
<GI
20
(BL-Vl
42 {BL-Vl
IB;::
:...i
IBRJ
A OR H
{V•Ol
.,
(V-0)
B;:
{Y)
TO
SHEET 2
B
tO-Vl 44 10-V) 10;;.
(V-Gl
IV-Gl 45
(V-G)
r"
...
RI (G-V)
46
(G-Vl
......
" ,
... , (G)
TO
-~
.,,
SPEAKER- IT
(V-BRl
'l;J
a
4T
IV-BAJ
0"
{V)
PHONE IR
!BR-VJ
48 tBR-Vl
~"
AG (V-S)
'.ff\\!
'9 IV-SJ
:~~
'~j
LK
IS-VI
I
50
(S-Vl
~~
(S-Vl
c
~-
('·,,;.,
~, ...
Fig. 23--2851-Type Telephone Set, Connections (Sheet 1 of 2)
Page 16
TCI Library: www.telephonecollectors.info

G3A6
HAt~OSET
\NOTE 31
TRMTR
n
I
I
L
RCVR
I Y-
~
(BL)
iY-BRi I-
(BK)
{Rl
~
{BR)
(VI
FRO M
SHEET
I
IV·G)
~
(V)
{S·V)
XL1 ..
. J.
.J ...
jJ
ISS 5, SECTION 503-60'1-101
NOTES·
I. CONNECTIONS FOR P!B RINGER SHOWN RINGER CONNECTIONS FOR SETS EOUlPPEO
WITH PIA RINGER SAME AS PIB EXCEPT {BLJ,(SJ,ANO (S-Rl LEADS ARE INSULATED
ANO STORED. (CURRENT MODEL PlA RINGERS DO NOT HAVE (BL} LEAD)
2. UNE SWITCH OPERATING SEQUENCE:
be MAKES
da MAKES
ob BREAKS
fQ BREAKS
3.CURRENT 26~18 TELEPHONE SETS ARE EQUIPPED WITH G3A6 HANDSET WHICH IS
WIRED DIRECTLY TO TELEPHONE SET EARLY PRODUCTION 285!-TYPE TELEPHONE
SETS WERE EQUIPPED WITH A GIZA tiANOSET USING A PLUG-ENDED CORO
*INSULATED ANO STORED.
H4CJ
CORO
(OK}
IR)
!Wl
!Wl
I - ----~PIB;m;GER -- ~
I '"" !Rl I
L _____ '_"_or_r_" ____ LJ
(BK)
1--~(BLJ
{Wl
I I
!'s-:,04,~- i I
I
',
1 I I I
~:i_:z:_n __ J I
I I
(BK)
I
RR
rl-
!
I I l
I
2.
I (0)
I
I
;..:-
I I -I
I I j
(V}
I L c I
IG-W)
I
-I \
{0-BK)
---
I
d I
. {W)
b
+'
' I
I
I
.__
..,
I I
I 9 I
(!]K)
1 t
{R)
-
--..?.
~"
(R-Gl
I
{W-BL)
IVI I
!SJ
I
~I
L-
'!!!
{W)
+
LINE SWITCH
~TI._21 __ _
42288 OR 425K
35AF3A OR 35C3A
-------O~L
Fig. 2~2851-Type Telephone Set, Connections (Sheet 2 of 2)$
Page 17
TCI Library: www.telephonecollectors.info

SECTION 503-601-101
HABLE B{I
CONNECTIONS FOR 1A KTS AND/OR STATION BUSY LAMP
WIRE OR LEAD
STATION
BUSY LAMP
LINE SWITCH
HOLD KEY STRAP
y
BR
G
O·BI< BK·BL
v.s G.V Y·BR
----
With·
1A 11
3 9 13 . 3
L2·c
out
1A1·1A2 4 3 13 3 9 3
13
L2·i·
·-----
1A
11
With
1,2·r
3 9 13
L2·i·
3
L2·i·
1A1·1A2 4 Lz·;·
13 3 9
Lz-;·
13 Lz;·
-· ------~-··-··--·-·-
"'Insulate and store.
t Network terminnl, undesignated terminals are on terminal board.
Page 18
18 Pages
TELEPHONE
SET
8;')1- 01·
2851-Type
TABLE C
PICKUP-SIGNAL KEY CONVERSIONS
KEY KEY LEAD
OPTION
0-W S-W G-R
Bl-BK
HPPPPP
9 9 9 9
-- ·- ---·-- ··-----· ·--
---""···~ -·--.--·--
HPPPPS
9 9 9 9
.. ----·---·--·
____ ,, _________ -----
---------
HP PP SS 9 9 9
11
-- ---------·--·------··---
HPPSSS !) 9
11 11
BR-BK
9
11
11
11
-----------------~- ----------
HPSSSS 9
11
11 11
11
----~-------------- ------ ----- ---------- ------~--
HPPP*P*S''' 9 9 6 6 3
HPP''P'''P'''S''' 9 6 6 6 3
''' For common signaling with intercommunicating or pri-
vate lines with
signaling under line .switch control.For lA
KTS, move (Y) line switch lead from terminal 4 to 11.
TABLE D
POLARITY GUARD CONNECTIONS FOR 2851-TYPE
TELEPHONE SET (P-90Dl 70 GUARD ASSEMBLY)
WIRE OR LEAD COLOR
Dial
BK
G-W
Line Switch w
REMOVE
FROM
NET.
RR
-----··-------···
c
c
CONNECT TO
GUARD
ASSY NET.
T
s
s
----·-··-·- -·---·------- -------- -------- -.- ------·-··----- ··-----~
Guard G
--- .. ·----- -·-- ·-~-----·--··-- -----
Assembly w
Note: For use when specified by local instructions
for encl-to-encl signaling installations.
KS·15724,L1
DIODE
L2i·~3
-·
---
·-
TCI Library: www.telephonecollectors.info