Bell System Practices 851 Identification, Installation, Connections, And Maintenance page 15

760A 666-TYPE
LSPK
TRMTR
R2FK
T7A OR
CD
TIIA CD
12) 17)
55-TYPE
CONTROL
UNIT
12)
2012 8
TRNSF
851- OR 2851-
TYPE
TEL SET
IW
CA
17)
TO KTS EQUIP
(SEE NOTE)
NOTE :
DO NOT TERMINATE
TI,RI,P3 OR IT,P4
OR IR,AG AND LK
LEADS .
Fig. 21-Uiock Diagram of 3-Type (MD) Speakerphone
Control Unit Located Near Stationt
8~1CM-TYPE OR 2851CM-TYPE
TEL SET
CONN
CABLE
THE 82CM-TYPE CONNECTING
BLOCK ARRANGEMENT IS
RECOMMENDED FOR EXPOSED
WIRING .
Fig. 22-.Biock Diagram of 4A Speakerphone Located
at Station Using 82-Type Adapter
ISS 8, SECTION 503-601-101
851BT-TYPE OR 28518T-TYPE
TEL SET
M16H
CORD
TO TERMINATE MI6H CORD
ON TERMINAL STRIP OF
851- OR 2851- TYPE
TELEPHONE SET, liSE
161A ADAPTER
Fig. 23-Biock Diagram of 4A Speakerphone Located
at Station Using 223D Adapter
R
A ORH
8
!Nb~[wt>
(NOTE
1)__.
r--f-"
ET
41
(V-8L)
ER
42
(BL-V)
A OR H
43 (V-0)
(NOTE 3)__.
EB
44
(0-V)
NOTES '
4
,/"'
lt
(V-8L)
A
(W-8L)
~
(BL-V)
z
(BL-W)
7
(W-0)
i
(V-0)
~
(O-W)
IO (0-Vl
~
n
t
+
j-
+
PU
3]
~
KEY
EXCLUSION
SWITCH
(P-21F938)
8121 69381
I. STORED SPADE-TIPPED LEADS OF LINE TO BE EXCLUDED.
2 . WHEN OTHER THAN LINE liS EXCLUDED ON lA KTS, DISCONNECT,
INSULATE AND STORE (0-W) LEAD FROM TERMINAL 4. CONNECT
BALANCE LEAD OF LINE INVOLVED TO TERMINAL 4 .
3. FOR !AI OR IA2 KTS, CONNECT (0-W) EXCLUSION LEAD TO
TERMINAL 10. AI GROUND MUST BE SUPPLIED DIRECTLY TO
EXCLUDED STATION.
Fig. 24-Exclusion Switch Connections
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