AT&T 4A Manual

BELL SYSTEM PRACTICES
AT&TCo Standard
1. IDENTIFICATION
The 4A speakerphone system is a hands-free
1.01
voice switched system for use as a telephone
adjunct and is a replacement for the 3B speakerphone
system.
The 4A speakerphone system consists of a
1.02
transmitter, loudspeaker set, power unit,
and either a connecting block or adapter that when
connected to a suitable telephone set, provides:
Hands-free telephone operation
•
On-hook dialing (when dial is not obstructed)
•
Automatic switching from speakerphone to
•
handset operation
Transmitter muting for private conversation
•
Visual indication when system is in use
•
Cutoff common ringer or other signaling
•
devices when desired
Components of the 4A speakerphone system
1.03
are shown in Fig. 2.
This system may be used with the lA, lAl,
1.04
and 1A2 key telephone systems and all PBXs.
Ordering Guide
Components which make up the 4A speakerphone
1.05
system are ordered separately as follows:
Set, Loudspeaker, 108A-•
•
Transmitter, 680A-•
•
Unit, Power, 85Bl-49
•
either
Block, Connecting, 82A-49
•
or
SSP 512-700-100-i01_19 73-05-Ql.jpg
Scanned by Frank Harrell, (Cowboy Frank) Castle Rock, Colorado Mar 02,2012 23:12:47
4A SPEAKERPHONE SYSTEM
1.06
Standard length mounting cords will be 7 feet.
The M2FG cord of the 223A adapter is always 25
feet. The transmitter and adapter may be ordered
stJecifically with 14-foot cords. Example:
A 14-foot cord may be ordered for field replacement
for the loudspeaker set. Example:
1.07
other colors are desired, refer to Section 500-120-100.
Order the necessary components to complete the
system in any one of the promoted colors.
the following plastic parts in the desired color for
field replacement. Example:
1.08
© American Telephone and Telegraph Company,
Printed in U.S.A.
Adapter, 223A-49
•
Cord, Mounting, satin silver (-87) 7 foot
•
•prom ted colors: Black ( -03), Green (-51),
White (-58), and Light Beige (-60).
Mounting cords are available only in satin
silver ( -87), and in 7- and 14-foot lengths.
Transmitter, 680-•, equipped with 14 foot cord
Adapter, 223A-49, equipped with 14 foot cord
Cord, D20N -87, 14 feet.
The transmitter and loudspeaker set will be
shipped in the four promoted colors.
Housing, 108Al-•
Cover, 680Al-•
4A speakerphone circuitry:
(1) T h e 4A s p e a k e r p h o n e incorporates a
voice-switching circuit which permits a
substantial increase in receiving volume, eliminates
singing, and essentially eliminates far-end talker
echo.
(2) When there is no transmission of speech,
gain is automatically removed from the
transmitter circuit and added to the loudspeaker
circuit. This avoids a singing condition while
receiving.
1973
SECTION 512-700-100
Issue 1, May 1973
If
Order
Page 1