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

BEU SYSTEM PRACTICES
AT & TCo Standard
SECTION 503-601-1 01
Issue 8, February 1980
851- AND 2851-TYPE TELEPHONE SETS
IDENTIFICATION, INSTALLATION, CONNECTIONS, AND MAINTENANCE
1. GENERAL
1.01
This section contains information on the 851-
and 2851-type telephone sets.
1.02
This section is reissued to:
• Add additional ordering information
• Update dial wiring diagram information,
Fig. 27 and 29
• Add cable routing in current 851CM and
2851CM telephone sets, Fig. 30 and 31.
2. IDENTIFICATION
2.01
The 851BM (MD) or 851CM (rotary dial)
and 2851BM (MD) or 2851CM (TOUCH-TONE"'
dial) are modular telephone sets with a G15A
handset and H4DU handset cord.
2.02
The 851CM (rotary dial) and 2851CM
(TOUCH-TONE dial) codes are available as
a completely assembled telephone set or a basic
modular telephone set base.
2.03
Purpose: Provides features of a 6-button
key station (5-line pickup and hold) at wall
installations.
2.04
Application: Used with central office or
PBX line circuits in lA, 1A1, 1A2, or 6A
key telephone systems. Both the 851- and 2851-type
sets are wired for 1A1, 1A2, and 6A systems. For
1A KTS, internal wiring changes must be made.
2.05
Ordering Guide:
(a)
Telephone Sets (Complete):
• Set, Telephone, 851CM-* (Fig. 1)
• Set, Telephone, 2851CM-* (Fig. 2)
NOTICE
Fig. 1-851-Type Telephone Set
(b)
•Telephone Set Bases:
• Base, Telephone Set, 851CM
• Base, Telephone Set, 2851CM•
(c)
Modular Items:
• Faceplate, 852A-*
• Faceplate, 2852A-*
Not for use or disclosure outside the
Bell System except under written agreement
Printed in U.S.A.
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