AT&T Bell System 7A Manual page 2

SECTION 5 1 8-450-1 00
CONTENTS
Station Busy Console (6B 1 ) With MW
0.
N. Station Restriction
TOUCH-TONE® Dialing
5. GENERAL MAINTENANCE
5 70A KSU
EXTERNALLY MOUNTED UNITS
A. 33A Voice Coupler
B. 20A-49 Apparatus Unit
C. 22A-49 Apparatus Unit
D. Loudspeakers
KTUs
POWER UNIT
TELEPHONE SETS
TROUBLE ANALYSIS
6. DETAILED MAINTENANCE
LINE CIRCUITS (400-TYPE KTU)
CO/PBX LINE RINGING ARRANGEMENTS
POWER FAILURE TRANSFER CIRCUIT (452A
KTU) . . .
INTERCOM CIRCUITS
A . Selector Circuit (424B or C KTU)
B. TOUCH-TONE Adapter Circuit (440A
or 478B KTU)
C. Voice and Tone Alerting Circuit (456A
or B KTU)
D. 2-Path Access Circuit (460B KTU)
PAGING CIRCUIT (457C KTU)
Page 2
PAGE
.
. . . . .
BACKGROUND MUSIC
65
MUSIC-ON-HOLD (45 1 A OR B KTU)
70
POWER DISTRIBUTION
70
79
1 . GENERAL
79 This section contains identification, installation,
1 .0 1
connection, operation, and maintenance
information for the 7A Communication System.
79
79 This section is reissued to:
1 .02
79 Rate the 832B, 2832B, 832C, and 2832C
•
telephone sets MD
79
Add information on the 832BM/2832BM,
•
79 832CM/2832CM, 832DM/2832DM, and 832EM/
2832EM telephone sets
79
Add information on the 575AM and 2575AM
•
telephone sets
80
Add information on the 400G, 451B, 456B,
•
80
460B, and 478B KTUs
80
Show the 440A KTU rated MD
•
80
Add information on the D-180656 kit of parts
•
for wall mounting of 832/2832 desk type
8 1
telephone sets
8 1 Change night transfer to ring transfer
•
Add information on connection of multiple
•
station-busy consoles
8 1
Clarify limitations on loudspeaker placement
8 1
•
82 Show new codes for keys in station-busy
•
consoles
82
Make corrections and additions to the
•
Ordering Guide
82
Revise and correct various tables and figures
•
82 Add new tables and figures
•
82 Revise text.
•
CONTENTS
PAGE
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