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SPECIAL SERVICE TELEPHONES
All our special service telephone stations are tabletop (portable) models.
The telephone circuit and accessories (induction coils, capacitors, and
ringers) are the same for all these telephones, greatly simplifying the
ordering of spare parts.
These telephones generally consist of the following:-
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One-piece aluminum alloy casing
and cradle,
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Steel base with control buttons
and optional signals,
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Removable base plate supporting
the capacitors, induction coil (anti-local interference), and other
accessories appropriate for each telephone,
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Dial for automatic Rotary system,
type No. 7019 with dial cord No. 7004B, to be specified when ordering.
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Dummy disc (cap) No. 2047B for
manual system with central battery, to be specified in order.
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Black enamel finish.
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Each ringer is independent of the
unit.
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The control pushbuttons (on/off)
are mounted on the base, in front of the casing, allowing for easy and
consistent operation.
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Adjacent to each button is a label
indicating the type of switching it controls.
Units for moderate climates: 2700 series telephones.
Units for tropical
climates: 2800 series telephones. See description cards beelow.
Telephone No. 2722B is also equipped with a No. 2034C winding coil.
A No.
2001A generator is used with Telephones Nos. 2719C and 2819C.
Telephone Dimensions
Nos. 2716C, 2716D, 2717B, 2723B: 157 x 155 x 200mm
Nos. 2719C, 2719D, and 2722B: 157 x 155 x 230mm
No. 2729B: 157 x 155 x 232mm
Two Line telephones
These telephones are designed to be connected to two lines:
1. One line
to the network (central telephone exchange with central battery).
2. The
other line to a private exchange (manual or automatic) with a central
battery.
Telephone Nos. 2716C and 2716D
Each user can:
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transmit and receive a call
directly on one of the predetermined lines;
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transmit and receive a call on the
other line by pressing an appropriate button on their phone; during a
call in progress on one line, block that line, connect to the other line
by a judicious operation of the buttons, and then resume the second
line, and so on.
Telephone No. 2716C
 This
telephone has 4 push buttons: 3 black buttons 1, 2, 3 (on) and 1 red release
button.
Nature of connections made by operating the buttons:
Direct connection of the phone to the network line (LA)
Buttons in
their normal rest position: When lifting the handset, the phone is normally
connected to one of the two aforementioned lines, for example, to line
Network (LA).
Network line (LA) blocking and connection to the private line (LB)
Pressing button 1: During an ongoing call on the network line, the
subscriber, by pressing button 1, is connected to the private line without
releasing the network line. Once the call on the private line has ended, the
phone is reconnected to the network line by pressing the red release button
4.
Direct connection to the private line (B)
Pressing button 2: This
directly connects the phone to the private line (LB).
Private line (LB) blocking and connection to the network line (LA).
Pressing button 3: During an ongoing call on the private line, the
subscriber, by pressing button 3, is connected to the network line without
releasing the private line; the return to the line (LB) is performed by
pressing button 2.
Return to normal position.
Release button 4: By pressing button 4, after
pressing any of buttons 1, 2, or 3, these buttons return to their normal
position and the phone is directly connected to the network line.
The buttons are returned to their normal position by hanging up the
handset.
Incoming Ring:
As calls are answered on both lines, each No. 2716C
telephone requires the use of: either two single magneto Bells No. 2388B
(one for each line); or one double magneto Bell No. 2389A with different
tones for each line.
Telephone No. 2716D
 4-button
telephone set: 4 buttons 1, 2, 3, 4, all with latching mechanism.
Nature of connections made by operating the buttons:
Buttons in their normal rest position: Simply lifting the handset does not
connect the set to the network (LA) or private (LB) lines.
Direct
connection of the set to the network (LA) line.
Pressing button 1 after
lifting the handset results in the desired number being obtained in the
usual way.
Locking the network (LA) line and connecting the set to the
private (LB) line.
Pressing button 2: When a call is in progress on
the network line, the subscriber can transfer a call to the private line,
without releasing the network line, by pressing button 2. The network line
will be blocked as long as button 2 is pressed. To return to the network
line, simply press button 1, which will return button 2 to its normal
position.
Direct connection to the private line (LB).
Pressing button
3 after lifting the handset.
Blocking the private line (LB) and
connecting the phone to the network line (LA)
Pressing button 4: During
an ongoing call on the private line, the subscriber can transfer a call to
the network line, without releasing the private line, by pressing button 4.
To return to the private line while releasing the network line, simply press
button 3, which will return button 4 to its normal resting position.
Buttons return to their normal resting position.
This operation is
performed either by hanging up the handset or by pressing another button.
Note: With both phones 2716C and 2716D, each of the two lines, network
and private, can be blocked alternately and at will. Connection of the phone
to the network line and blocking of the private line, which can in turn be
connected to the phone by blocking the network line, and vice versa.
Telephone No. 2723B
 Telephone with two push buttons.
The
phone is connected on one side to a private switch, and on the other side to
a network line via a junction switch. There is no junction circuit between
the private switch and the junction switch.
Nature of the connections
made by operating the buttons:
Buttons in their normal rest position:
Simply lifting the handset does not connect the phone to either the network
line (LA) or the private line (LB).
Direct connection of the phone to the
network line (LA) (junction switch).
Pressing button 1: After lifting the
handset, the call is transferred to the operator in the usual way.
Network
line (LA) lock and connection to private line (LB).
Pressing button 2
after pressing button 1: If a call is in use on the network line, the phone
can be connected to the private line, without releasing the network line, by
pressing button 2.
Returning to the network line is done by pressing
button 1 again, which had returned to its normal position when button 2 was
pressed.
Hanging up the handset returns the buttons to their normal
positions.
Incoming Ring:
Since incoming calls are received on two lines, this phone
requires the use of 1 dual magneto Bell No.
2389A with different tones for each line.
Auxiliary Call Line
Telephone No. 2717B
 This line is used when a subscriber needs
access to two lines connected to the same central office or private switch.
Incoming calls can only be received on one line; the other line is used
solely for outgoing calls when a conversation is in progress on the first
line.
This is a 3-button telephone: buttons 1 and 2 for activation, button 3 for
release.
Nature of connections made by operating the buttons:
Buttons in their normal position. By simply lifting the handset, the phone
is normally connected to the network line (LA). Transmission and reception
of calls are carried out on this line.
Locking the network line (LA) and
connecting the phone to the second line (LS).
Pressing button 1:
While a conversation is in progress on the first line, pressing button 1
connects the phone to the second line without reconnecting the first line.
The second line cannot receive any incoming calls and is only used to make
calls while the first line is busy.
Second line (LS) is locked, and the
telephone is connected to the network line (LA).
Pressing button 2: While a
conversation is in progress on the second line (LS) during the network line
lock, the phone can be reconnected to the network line without releasing the
second line by pressing button 2.
By successively pressing buttons 1 and
2, it is possible to alternately lock each of the two lines while
maintaining communication on the line connected to the phone.
Returning
the buttons to their normal position.
Pressing button 3. The phone is
normally connected to the network line (first line) by pressing button 3
after pressing buttons 1 or 2.
Hanging up the handset returns all the buttons to their normal rest
position.
Incoming Ring:
Only one ringer is used with this phone: Magneto Bell No.
2388B.
Connections:
For manual operation, connect terminals T and L.
Main Telephone and Auxiliary Telephone
 Telephone No.
2719C and No. 2719D
The main telephone is connected directly to the central office (to
the network line) and also to an auxiliary telephone.
The auxiliary
telephone
can be connected to the network line, but only via the main telephone, which
is equipped with a set of pushbuttons for intercom communication between the
central office, the main telephone, and the auxiliary telephone.
The main
telephone (No. 2719C and No. 2719D) is equipped with an indicator light that
signals to the main telephone when the network line is occupied by the
auxiliary telephone (No. 2712 or No. 2724).
Calls between the main telephone and the auxiliary
telephone are made either by a magnetic call device or a battery-powered call
device.
Telephone No. 2719C - Call by magneto bell
Four-button telephone with optical signal and white indicator lights, three
black buttons (1, 2, 3) for activation and one red release button.
Nature of connections made by buttons:
Buttons in their normal position.
Simply lifting the handset connects the telephone to the network line (LA),
and calls are received or transmitted in the usual way.
Locking the
network line (LA) and connecting the main telephone to the auxiliary
telephone.
Pressing button 1: When a call is active on the network line,
pressing button 1 blocks the line, and the main telephone is connected to
the auxiliary telephone.
Connecting the auxiliary telephone to the
network line.
Pressing button 2: All network calls are received by the
main telephone; however, network calls can be transferred to the auxiliary
telephone by pressing button 2 on the main telephone. The telephone circuit
of the main telephone is no longer connected to the network line, which is
connected to the telephone circuit of the auxiliary telephone.
Throughout
the connection, the white indicator lights remain illuminated in front of
the appropriate signal openings, indicating to the subscriber at the main
telephone that the network line is busy.
The main telephone can be connected
in parallel, allowing the subscriber at that telephone to
 listen.
Connecting the main and auxiliary telephones.
Pressing button 3. The
connection between the two telephones, main and auxiliary, is established by
pressing button 3. The auxiliary telephone is called by pressing the call
button.
To call the main telephone, the call button on the auxiliary
telephone must be pressed.
Note that the main telephone can still be called
via the network line.
Returning the buttons to their normal position.
Pressing button 4. All buttons are returned to their normal position by
pressing button 4.
Hanging up the handset does not return any engaged
buttons to their normal rest position.
Calls between the main and
auxiliary telephones:
Call-by-call device; each telephone is called by
pressing the call button on the calling telephone. (Generator No. 2101A).
Ringtones:
This telephone is equipped with two Bells, one for
network calls and the other for calls to the auxiliary telephone.
To
avoid using two separate ringers, magneto bell No. 2389B should be
installed.
Telephone No. 2719D - Battery-Powered Calling
Telephone No. 2719D
is similar to Telephone No. 2719C in both construction and intercom capabilities,
but differs from Telephone No. 2719C in the calling mechanism between the main
telephone and the auxiliary telephone.
Battery-Powered Calling Mechanism:
A
6-volt battery pack is required, along with two call buttons and two DC
ringers at each end of the auxiliary line. These are not supplied with the
telephone. The local battery supplying the conversation circuit between the
main and auxiliary telephones can also be used to power the ringing circuit,
provided that the voltage required for the ringing does not exceed the
battery voltage.
Incoming Ring for Network calls:
Bell No. 2388B.
Connections:
For
manual service, connect terminals T and L.
Serial Telephones (Intercom Installations)
Telephone No. 2722B - Network Line
 Two or more
telephones are connected in series to a single
network line.
Each telephone can connect to the network line without the
intervention of another telephone, provided, of course, that the line is free.
The telephones can communicate with each other either via a local line common
to all telephones or via a private switch.
All telephones are identical and
equipped with an indicator light and switching buttons.
When one of the
telephones is connected to the network line, the indicator lights on all
telephones are active and indicate that the line is in use. The network is
busy; the other telephones located after this telephone are connected to the
network line. These telephones can communicate with each other via the local
exchange circuit or the private intercom.
The Telephone No. 2722B has an indicator light and 3 buttons:
Black buttons 1 and 2 are for latching and red button 3 is for calling the
local line.
Nature of connections made by operating the buttons:
Buttons in their normal position:
Lifting the handset does not connect
the telephone to the network or local lines.
Connecting a telephone to the
network line (LA):
Pressing button 1: The telephone is connected to the
network line (LA), and the call is transmitted normally; the busy signals
are functioning.
Locking the network line (LA) and connecting to the
circuit Local (LB). Press button 2 after pressing button 1.
When a call
is in progress on the network line, pressing button 2 connects the phone to
the local circuit, but the network line remains connected. The call is then
routed normally on the local circuit.
To return to the network line,
simply press button 1, which re-establishes the phone's connection to the
network line.
Busy indicators remain in their active state.
Connecting the phone to the local line (LB).
Pressing
button 2. The phone is connected to the local line by pressing button 2.
The phones are connected to a private switch: calls are routed in the
usual way.
Calls from the phone via the local line.
Pressing
button 3. This button is used only for calling phones via the local line
when a private switch is not in use. Differentiation between phones to be
called will be achieved using a coded ringing system.
Returning the
buttons to their normal position.
Hanging up the handset
returns the buttons to their normal resting position.
Incoming ring:
The type and
number of additional rings to use will generally depend on the phone
installation and also on whether incoming calls from the network are to be
received by one or more phones.
a) Connecting telephones to a private switch:
For telephones intended to receive network calls, two magneto Bells No.
2388A or one double ringer Bell No. 2389A will be used, one ringer connected to
the network line and the other to the private switch line.
Telephones not
intended to receive network calls are equipped with a magneto Bell No. 2388B
connected to the private switch line.
b) Connecting telephones to a
local circuit:
Telephones receiving network calls will be equipped with a
magneto Bell No. 2388B.
For calls between telephones, a battery pack is
required, and each telephone must have a DC ringer. These accessories are not
supplied with the telephones.
The 6-volt battery must power the local
circuit for the DC ringers and the operation of the network line occupancy
signals. Connections: For manual service, connect terminals T and L.
Serial Telephones (3 Network Lines)
Telephone No. 2729B
 All phones are connected
in series to 3 network lines and can also communicate with each other via a
private switch.
All phones are identical and are equipped with 3
signals, one per network line, and a set of switching buttons.
Each
subscriber can, by pressing an appropriate button on their phone:
1)
Transmit a call directly to the network, provided the corresponding network
line is free;
2) Receive a call directly from the network, if the phone
is equipped with a ringer for each network line to receive calls;
3)
Receive and transmit any internal communication directly via the private
switch line;
4) Receive a call from the network, after notification
from one of the telephones directly handling incoming network calls.
Network Line Identification
Each of the three
network lines can be identified by equipping the telephones directly handling
incoming network calls with different bell tones for each network
line.
Busy Signal
Connecting a telephone to a
network line automatically activates the busy signal corresponding to that
line on each of the other telephones in series; all telephones connected to the
network are disconnected from that line.
Note: When a busy signal is
active on a telephone, do not press the button corresponding to the busy line,
as this will disconnect any ongoing conversations on that line for
subsequent telephones.
Telephone No. 2729B has 3 indicator lights and 5 buttons:
black buttons 1, 2, and 3 for network lines, a black button 4 for the
private line and a red button 5 for callback.
Nature of connections made by
button operation:
Buttons in their normal rest position. Lifting the
handset does not establish a connection to the network (LA) or private (LB)
lines.
Connecting the extension to one of the 3 network (LA) lines.
Pressing button 1. After lifting the handset, the extension is connected to
network line 1. By pressing button 1, all busy signals on other extensions
corresponding to line 1 operate automatically; the call is received or
transmitted in the usual way.
Pressing button 2. The phone is
connected to network line 2, and the busy signals for line 2 operate as
described above.
Pressing button 3. The phone is connected to network
line 3.
The phone is connected to the private switch line (LB).
Pressing
button 4. The phone is connected to the private switch line, and calls are
routed normally.
Network line (LA) is locked, and the phone is connected
to the private line (LB).
Pressing button 4 after pressing buttons 1, 2,
or 3. When a call is in progress on network line 1, 2, or 3, pressing button
4 connects the phone to the local circuit without releasing the network
line. The call is sent in the usual way over the local (private) circuit.
To reconnect to the network line, simply press the small red button 5
located next to and in front of button 4, which re-establishes the
connection between the phone and the network line.
Buttons return to
their normal position.
Hanging up the handset or pressing the red button
5 returns the buttons to their normal position.
Taken from the BTMC Catalogue - 1936 and 1952
Description cards and telephone wring diagrams
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BELL
TELEPHONE MANUFACTURING Co.