AT&T 2833 Series Guide

BELL SYSTEM PRACTICES
AT & TCo Standard
SECTION 50 3- 702-110
Issue 5, December 1980
TELEPHONE SETS
833- AND 2833- TYPE
IDENTIFICATION, INSTALLATION, CONNECTIONS, AND MAINTENANCE
1. GENERAL
1. 01 This section contains information for the
833- and 2833-type telephone sets. The 833-
(rotary dial) and 2833- (TOUCH-TONE®dial) type
key telephone sets are special plug-ended 20-button
key telephone sets, initially designed for use with
the
14A (MD) Communication System, (COM KEY*
1434). These sets also may be used with 21A
Communication System (COM KEY 2152). For
information on COM KEY Systems, refer to the
appropriate section
in Division 518.
1. 02 This section is reissued to:
• Add information on automatic and manual
DO-NOT-DISTURB feature
• Add D-180990 Kit of Parts for 4-wire service
• Add D-180883 Kit of Parts for electromagnetic
interference (EMI)
• Show 14A Communication System MD
• Add lead designation for 21A Communication
System, Fig. 6 through
13.
2. IDENTIFICATION
2. 01 The 833BM, 2833BM, 833CM, and 2833CM
(Fig. 1) are modular type telephone sets
and will replace the
833B, 2833B, 833C, and 2833C
telephone sets, respectively, which are hereby rated
MD. The 833DM, 2833DM, 833EM, and 2833EM
are al
so modular sets and are electrically and
functionally equivalent to the 833BM, 2833BM,
833CM, and 2833CM sets, respectively, except that
they have been adapted for wall mounting. The
modular sets will all
be equipped with a G15A-50
*Trademark of AT&T Company
handset and H4DU-50 handset cord which
wi ll plug
into a
616T jack mounted on the left front of the
telephone set base (Fig. 2). Current production
models of these sets also are equipped with an
improved line switch and an automatic button
restoral (ABR) feature. Some early production
BM
and CM sets were not so equipped.
Fig . 1- 2833CM Telephone Set
2.02 The 833B (MD), or 833BM, 833DM and 2833B
(MD), or 2833BM, 2833DM telephone sets are
equipped with a 647K5 key in the lower key position
consisting of a hold button, six line buttons, and
three intercom buttons. A 647P5C key is located
in
the upper key position consisting of a RECALL
button, a Privacy Release (PRIV RLS) button, and
eight line buttons. The privacy circuit board is
factory installed and wired (Fig.
2).
2. 03 The 833C (MD) or 833CM, 833EM and 2833C
(MD) or 2833CM, 2833EM te lephone sets are
NOTICE
Not for use or disclosure outside the
Bell System except under writt en agreeme nt
Printed in U.S.A. Page 1

SECTION 503-702-110
Fig. 2-2833BM Telephone Set Bose
similar to the above sets except a 647N5C key is
located
in the upper key position consisting of a
RECALL button, a RING TRANSFER button (not
connected), and eight line buttons. The RING
TRANSFER button must
be wired in the field
when ring
transfer option is provided (Table E).
Note: In early production 833C and 2833C
telephone sets the RING TRANSFER key was
factory wired.
2.04 The DM and EM (wall type) sets and BM
and CM (desk type) sets are not interchangeable
due to the mechanical changes
in the handset
hanger and the new 6Cl-50 housing.
2.05 An adapter (833A-50) will be furnished with
each
DM and EM telephone set for wall
mounting. The switchhook of these sets has been
designed to hang vertically to the left of the
housing. The sets are equipped with a hard-wired
mounting cord which can
be coiled up and concealed
in the adapter or the cord can
be extended down
the wall through a notch in the adapter for
termination to appropriate connector-ended cable.
All maintenance can
be performed on internal
components of these sets without removing the
set
from the wall.
2.06 All of the 833- and 2833-type sets provide
the same basic services such as pickup, hold
and illumination, and intercom. They are equipped
with a loudspeaker to provide tone and voice
signaling. The level of the tone is adjusted
by a
volume control knob located under the
right side
Page 2
of housing. Two or more CO/PBX lines may be
conferenced by simultaneously depressing the buttons
associated with the lines to
be conferenced. The
three intercom lines may also be conferenced.
Intercom and CO/PBX lines cannot
be conferenced
except in the
21A communication system when the
3rd
IC path is terminated on a multipurpose button.
Automatic button resotration restores all depressed
buttons to the unoperated positions when the handset
is replaced.
2.07 Multiline conferencing is a feature of these
telephone sets. Since there is
no amplification
involved, this type conferencing is limited. When
lines
are conferenced, using this manner of
conferencing, distant stations may have trouble
hearing each other and transmission
is not guaranteed.
Note: •when a telephone set is modified
for 4-wire service, multibutton conferencing
between 2- and 4-wire systems is not
recommended .•
2.08 The 833- and 2833-type telephone sets may
be used with either the 3-type (MD) or 4A
speakerphone system.
•
1\
The limited number of mounting cord
conductors places a restriction on the
location
of 3-type (MD) speakerphone
components unless it is desired to give
up one pickup line. Refer to
Section 512-620-487 or 512-740-471
for connection information for
the 3-type (MD) or 4A speakerphone
system.
2.09 The 833- and 2833-type telephone sets are
available in Ivory (-50) only. These sets
will
be shipped with a disposable faceplate, so it
is necessary to order
the proper 833A or 2833A
faceplate separately (Table B).
2.10 Any CO/PBX line may be optionally wired
to ring
at one to four stations (maximum
of two in addition to two
attendant stations).
Refer to Section
518-450-110 for strapping information.
When common audible ringing is wired
to a station other than one of the
attendants station that station cannot
have the ring transfer option. The
21A communication system can

have up to three (3) attendant
stations with optional wiring.
Ordering Guide
2.11 For telephone set and replaceable component
ordering guide, refer to Table
A. See Table
B for color and faceplate ordering information.
2.12 The following optional apparatus may be
associated with desk type 833 and 2833 sets
(order as required):
• D-180656 Kit of Parts [to provide a wall
shelf mounting arrangement] consists of the
following:
1-840362446 shelf
1-840362479 clamp
1-801812553 screw
Note: •If a (wall-type) set is to be installed,
a
DM or EM code set is available.f
• Diode 533K or equivalent (order one for
each rotary dial station to
be restricted)
• 870Al or 2870Al TOUCH-A-MATIC "' adjunct,
for connections refer to Section 501-164-201
TABLE A
ISS 5, SECTION 503-702-110
• 4A Speakerphone (order one each of the
following for each station to
be equipped
with speakerphone). For additional information
on 4A components, refer to Section 512-700-100.
Loudspeaker,l08AA-tt (includes 7 foot D20N
mounting cord)
Transmitter, 680AE-H (includes 7 foot
D8S
mounting cord)
Adapter, 223D-49 (includes 7 foot Ml6H
and
25 foot M2FG cord)
Unit, Power, 85Bl-49
• Ringer, ElCM (one for each CO / PBX line
to be wired for power failure transfer)
• D-180486 Kit of Parts (privacy circuit board),
order one for each station to
be locked out.
Can be added to the 833C, CM, EM, 2833C,
CM, or EM telephone set.
t Add color suffix.
*The transmitter and loudspeaker set will
be shipped in one of five promoted colors,
Black (-03), Ivory (-50), Green (-51), White
(- 58), and Light Beige (-60).
TELEPHONE SETS AND REPLACEABLE COMPONENTS
ORDERING GUIDE
FACE ·
HANDSET
TEL SET
BASE HOUSING DIAL
KEY PLATE' HANDSET
CORD
LAMP
833 BM ·50
833BM
6 17P5C
647K5
83 2A -5 0 647N5C
833C M·50 833
CM
BC or
647K 5
B
CA
6- 17P5C
833, \ ·
833 DM ·50
8- 10 99 8678 617K5
6CI·50
6 1 7N5C
833 EM ·5 0 8
4099 8694 6
47K 5
6 17P5C G! 5A
·50 11 4D U·5 0
fi lA
2833 61\1 ·5 0 2
H3 3BM
6- 17K 3
832 A·50
647N5C
2833CM -: i0
283 3CM
6- 17K5
3'>AF:lA
~~3:J A ·
2 83 3DM ·50 8
40998C86
647P5C
6
47K5
6CI ·5 0 6
17 N5 C
2
833 EM -50 810998
702
617K5
* See Tabll • B for ('olor s uffi x.
P~ge 3

SECTION 503-702-110
• Transmitter, 683AE-50 (for HF AI feature
of COM KEY 2152), also includes a
DO-NOT-DISTURB switch
• Adapter, 268A (for mounting 683AE-50
transmitter when using DM or EM wall type
telephone sets)
• .Key, 688A manual DO-NOT-DISTURB option.
This key is intended for use with the 14A
communication system.
It can also be used
with
21A communication system at stations
not equipped with the HFAI option.
• Kit of Parts, D-180990 (4-wire interface for
the
14A and 21A communication system)
consists of the following:
1-842533440 relay assembly consists
of:
1-Allied control relay KHX-213
1-842533457 mounting bracket
8-Conductor assemblies
2-FH 0.086-32 by 5/16-inch tapping
screw
1-446F diode
1-801682956 (P-168295), 6-40
by 5/16-inch
BHM screw
1-801809245 (P-180924), 4-40 by 5/16-inch
BHM screw.
3. INSTALLATION AND CONNECTIONS
3.01 Install telephone sets at desired locations,
making sure
that any options are installed
before telephone
set is connected. See Fig. 6
through
13 for schematics of 833B, 833BM, 833DM,
2833B, 2833BM, 2833DM; 833C, 833CM, 833EM,
and 2833C, 2833CM, 2833EM telephone sets,
respectively.
3.02 All DM and EM (wall type) sets are shipped
with an 833A-50 adapter, screw, and clip
(Fig.
3) which are used for mounting the telephone
set to a vertical surface. Install the 833A-50 adapter
and telephone set as follows.
Page 4
Note: If HFAI is to be installed, refer to
paragraph 3.05(g) for installation information.
(1) Mount the adapter to the wall or vertical
surface as shown
in Fig. 3, using appropriate
fasteners (Section 080-720-105).
If the mounting
cord is to
be dressed down the wall, it is necessary
to pass the cord through the notch
in the adapter
before final
attachment of the adapter to the
wall (Fig. 4). If the cabling enters through the
wall, the mounting cord may
be contained within
the adapter.
(2) Remove faceplate and housing from telephone
set .
(3) Hang the telephone set on the adapter from
the headed rivets
that protrude from the
base pan (Fig.
4).
Note: It may be necessary to slightly bend
the top slotted portion of the adapter so the
headed rivets of
the base pan will align
properly.
(4) Secure the telephone set base with the clip,
and screw
at the bottom of the adapter
(Fig.
3) .
(5) Install telephone set options (see paragraph
3.05).
(6) Replace housing and faceplate.
3.03 A D-180656 Kit of Parts ma y be ordered
separately for shelf mounting of all
B, BM,
C, or CM sets. The 840362446 shelf should be
mounted to a wall or vertical surface and, after
placing the telephone set on the shelf, secure set
with retainer clamp and screw furnished with the
shelf. Refer to
paragraph 2.12 for ordering
information.
3.04 To install telephone set options the faceplate
and housing must
be removed and the dial
lifted from its mounting brackets. Use a KS-2110711
releaser or equivalent to release the faceplate catch.
Caution: The ten button key(s) in
this set is equipped with special
low-friction plastic parts. Special
care is required when removing or
replacing these keys to avoid cracking
or breaking the plastic hooked end

683AE TRANSMITTE
268A ADAPTER
Fig. 3-833A-50 Adapter with 268A Adapter and
683AE Transmitter
of the latchbar projecting from the
end of the key. When removing a
key, avoid twisting or distorting the
hook. When installing a key, make
sure the hook is properly engaged
over the edge of the pivot arm before
tightening the mounting screws of
the key.
Caution: Unplug the set before
making wiring changes involving
adding or moving spade tipped leads
on the terminal board (e.g., privacy
option).
ISS 5, SECTION 503-702-110
3.05 Options are installed as follows:
(a) Station Restriction (833-type telephone
set):
(1) Install 533K or equivalent diode between
network
terminals RR and F. Terminate
negative lead of diode on terminal F (arrow
on diode pointing toward F), with positive
lead on terminal
RR.
(2) On telephone set terminal board, move
two (G) leads from terminal
22 to 4 and
move two (R) leads from terminal 4 to
22.
(b) Station Restriction (2833-type telephone
set): On telephone set terminal board,
move two (G) leads from terminal
22 to 4 and
move two (R) leads from terminal 4 to
22.
(c) Privacy Circuit 833C, 833CM, 833EM,
or 2833C, 2833CM, 2833EM (D-180486
Kit of Parts):
(1) Mount privacy circuit board on the two
standoffs located
at the left front of the
telephone set base (Fig.
2) using mounting
screws furnished with the telephone set.
(2) Refer to Table C for connections.
(3) To test privacy circuit refer to 3.06.
(d) Disable Privacy Circuit (D-180486
Kit of Parts) 833-type telephone
sets: Remove (0) and (BK) leads of privacy
circuit from the telephone
set terminal 8 and 12,
respectively, and insulate and store.
(e) To Disable PRIV RLS (part of top
key) 833B, 833BM, 833DM or 2833B,
2833BM, 2833DM telephone sets: Move
(0-BK) lead of privacy release key from telephone
set terminal 10 to 15, see Table G.
Page 5

SECTION 503-702-110
Fig. 4-Mounting Telephone Set Base onto 833A-50 Adapter
(f) RING TRANSFER (833C, 833CM,
833EM or 2833C, 2833CM, 2833EM
telephone set only):
(1) Refer to Table E for connections.
(2) Refer to Section 518-450-102 for KSU
strap addition.
Note: Early version of the 833C and 2833C
telephone sets had the RING TRANSFER
feature factory wired. Current
833C, 833CM,
833EM and 2833C, 2833CM, 2833EM telephone
sets are not factory wired for RING TRANSFER.
(g) HANDS-FREE ANSWER INTERCOM
(HFAI):
(1) If feature is to be added to DM- or
EM-type set, a 268A adapter must be
used as follows:
Page 6
(a) Mount 268A adapter onto 833A-50 adapter
with two screws as shown
in Fig. 3
with the tabs of
the 268A adapter facing
outward from the vertical surface. The
683AE-50
transmitter is secured by sliding
the
transmitter downward between the tabs
on the adapter. The telephone set end of
the transmitter cord enters the telephone
set and is attached to the telephone set base
at the small notch on the top edge of the
base panel. The excess cord is stored
in
the 833A-50 adapter.
(2) For B/BM or C/CM (desk type) sets, the
transmitter cord will enter at the rear of
the set.
(3) Refer to Table D for connections.
Note: It may be necessary to slightly reduce
the volume
at the telephone set if distortion
or feedback is noticed when the HFAI feature
is used.
(4) •Included as part of the 683AE transmitter
(furnished with the HF AI feature) is a

manual DO-NOT-DISTURB switch. Depression
of the switch (Fig.
3) prevents voice signaling,
alerting tone, and activation of the microphone.
A distinctive tone
is sent to any station that
is calling another station on dial intercom
when the called station does not want to be
disturbed. The only signal
that can be received
by a station or answering position with the
DO-NOT-DISTURB switch activated are tone
ringing and the
alerting tone and one way
voice signaling associated with an
automatic
signaling intercom.
(h) Automatic and Manual DO-NOT-
DISTURB (DND) Feature, COM
KEY 1434 and 2152
(1) This feature permits a station user to
block any incoming dial intercom and DSS
calls. Use of this feature alerts the calling
party that the called party does not want to
be disturbed. This is accomplished by
returning
an audible tone (500 Hz, continuous) to the
calling
party whenever either the automatic
or manual DND feature is activated. In COM
KEY 2152 system, a visual signal is also
provided on the DSS console when
the manual
DND feature
is in use. The COM KEY 2152
system currently provides a manual DND
option
but it is only available on station sets
that are equipped with the HFAI option. The
major difference between the automatic and
manual DND options
is that automatic is
activated only when the station
set is off-hook,
while the manual can
be activated with the
station on-hook
or off-hook.
(2)
Refer to (Fig. 14) for telephone set
modificaton for automatic DND feature.
(3) Refer to Section 518-450-102 for necessary
KTU and KSU connection information with
the DND feature.
(4)
For manual DND feature with these
telephone sets, a 688A key must be ordered
separately and installed
as follows:
(a) Attach the key
on the right side of
the telephone
set baseplate and under
the
set housing.
(b) Modify the telephone
set wmng and
terminate the spade-tipped key leads
I SS 5, SECTION 503 -702-110
as shown in the appropriate modification
table (Fig.
15).
(c) Refer to Section 518-450-102 for necessary
KTU and KSU connection information
with the DND feature.
(i) Four-Wire Service (D-180990 Kit of
Parts, Ordered Separately).
(1) Mount the relay assembly in the front
right-hand corner of the telephone set
using mounting bracket and screws as shown
in Fig.
5.
(2) Connect the relay spade-tipped leads as
shown in Table I and Fig.
16.
(3) Refer to Section 518-450-102 for 14A (MD)
communication system and Section
518-450-110
for 21A communication system interconnecting
wiring arrangement.
(j) Electromagnetic Interference (EMI)
Mitigation, D-180883 Kit of Parts
(ordered separately).
(1) An amplifier printed wiring board assembly,
equipped with RFI suppression
is available
and is a direct replacement for the amplifier
board furnished with these telephone sets
.•
3.06 Privacy Circuit/Privacy Release Test:
(a) Busy out a line using another station (Station
X) . At the set with the privacy circuit to
be tested (Station Y) go off-hook on that line.
Station Y should be locked out. Hang up Station
Y.
(b) If Station X has a privacy release key,
depress it. The lamp under the busy line
will indicate it is on-hold. Station Y should now
be able to pickup the line on hold. Release the
privacy release button, Station X and Y should
now
be bridged. Hang up Station Y.
(c) If Station X does not have a privacy release
key
but does have a privacy circuit he cannot
allow Station Y to bridge onto
the call without
excluding himself.
(d) With the line still busied
out by Station X
and Station Y not bridged, depress a different
P age 7

SECTION 503-702-110
842533440
RELAY ASSEI'IBLY
0.086-32 X 5/16- IN.
FH TAPPING SCREW (2)
~ "'' "''''' ,, _,,,,,,,
4- 40 X5/16 IN .
BHM SCREW
Fig . 5- .Mount i ng Location for 4-Wire Relay Assembly.
line on Station Y and go off-hook. While ho lding
that line button depressed bridge onto the line
that was busied out by Stat i on X. Station Y
should
be locked out of both lines.
3. 07 When insta ll ing faceplate, insure th at the
co ll ar is in place on the key. Place the tabs
into slots in fr ont of the faceplate ope ni ng in the
housing and l
owe r sl ow ly over the di al and key
co ll ar un til almost in place. Use a KS - 21107L1
releaser or equivalent to release the faceplate catch
and
seat the faceplate.
3. 08 The 647 K5 and 647P5C keys use designation
ta b s, forms E -583 7 and E-66 72 (n ew preprinted
Page 8
designation tabs for feature designations). The
forms are shipped with the telephone sets.
To
install, squeeze sides of the cap and remove. Insert
designation tabs and replace cap with locking tabs
along the horizontal axis of the key.
3.09 For telephone set number designation, use
form E-10360, E
-1 0364-§, or E-10368-§ for
rotary dial sets and form E-10361, E-10365-§, or
E-10369-§ for TOUCH-TONE dial sets.
3. 10 Refer to Fig. 6 through 13 for telephone set
sc hematics.
§ Requires th
at area co de be added.

3.11 Refer to Section 512-620-487 or 512-740-471
for connections to 3-type (MD)
or 4A
speakerphone system, respectively.
3.12 If Power Failure Transfer feature is to be
provided, use an external ringer (E1CM)
and connect as shown
in Table H.
4. MAINTENANCE
4.01
Maintenance of the 833- and 2833-type
telephone sets should
be limited to checking
for loose or broken connections and replacement
ISS 5, SECTION 503-702-110
of items listed under Ordering Guide table as
replaceable components.
Telephone set should not be carried
by the switchhook since this applies
excessive strain to the line switch
and could cause a trouble condition.
4.02 The current production 647-type key has
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, key collar, and button for
lamp replacement.
Page 9

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