Improved Telephone Systems for Common or Party Telephone Lines, and Switch Devices for use therein
Year: 1897

page_text: Date of Application, 10th Feb., 1897
Complete Specification Left, 9th Nov., 1897-Accepted, 11th Dec., 1897
“Improved Telephone Systems for Common or Party Telephone Lines,
and Switch Devices for use therein."
I, JULIUS HENRIK WEST, of 3, Monbijouplatz Berlin in the Empire of Germany,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has for its object special switch devices for common or party
telephone lines, that is to say, lines or conductors which may be used in common
from several speaking places. These switches are characterised by such an
arrangement that whilst one speaking place is being used the switching on of the
other speaking places into the wire is prevented either by bolting or locking the
receiver hook switch, or by bolting or operating another suitable interruptor of
the speaking current circuit of the unused speaking places. The arrangement is
in general such that only one of the speaking places connected with the wire can
be called from the central office.
For the purpose of description it will be assumed that there are four speaking
places which will be referred to as I, II, III and IV. These four speaking places
are connected parallel one with another by means of four branch wires with the
main double wire running to the exchange or central office. The apparatus at
these speaking places differs from the ordinary speaking places with battery or
induction call merely by the call being omitted, whilst an electro-magnet is
inserted, the armature lever of which is arranged to serve as a bolt for bolting
or fastening the lever of the receiver hook switch when im repose; this latter is
also provided with a special contact. Only one of the speaking places I is pro-
vided with a call, which however is not thrown into action in the ordinary manner,
but is connected through the armature lever of the electro-magnet and its contact
with two speaking wires leading to this speaking place.
The actual speaking and calling apparatuses of the four speaking places need
not be described as they are non-essential for the explanation of the present inven-
tion. It is sufficient to state that these apparatuses are inserted between the
clamps or terminals, and that the course of current from the one terminal through
the speaking place to the other terminal is interrupted when the receiver is sus-
pended on the hook.
If it be desired to utilise a speaking place, the receiver is first removed from the
hook and them a call current is despatched. On lifting off the receiver, for
instance, at speaking place II, the lever of the hook switch will rest against the
upper contact, whereby a wire is laid to earth. A current therefore flows from a
suitably located battery through an electro-magnet which is connected with said
wire. The electro-magnet will attract its armature, and the wires of the various
speaking places will thus be connected with the battery, the armature lever rest-
ng against a contact, and the electro-magnets hereinbefore mentioned, which are
D

page_text: connected with the wires, will therefore attract their armatures and thus lock the
book switches of the unused speaking places I, III and IIII; in the speaking
place II which is in use this does not however take place, because the switch lever
is already out of engagement with the bolting lever. In speaking place I by the
movement of the locking lever the call is also cut off. Speaking place II can thus
use the same line without the other speaking places being able to hear or interrupt.
When all the receivers are suspended on the hooks, the call is always connected
with the line, so that thus speaking place I may be called from the office.
The following is a modified switch device on the same basis as that just
described, but differing somewhat in details.
The switching on of the speaking places into the main double wire leading to
the exchange or central office takes place by means of relays, whereby one of the
former four wires is rendered superfluous, as the electro-magnets which in the
switch herein before described were connected with one wire are here attached to
another of the wires, so that one wire is dispensed with. The speaking and call-
ing apparatuses are, as in the preceding example, connected with two of the wires.
The speaking places have no call, and when the receiver is suspended on the hook,
the course of the current between the clamps or terminals on which the wires rest
is interrupted.
When the receiver is suspended, the electro-magnets at the various speaking places
are connected to earth through the contacts. If the receiver, for instance at speak-
ing place II, be lifted off the hook, in this speaking place the wire of the hook
switch is laid to earth instead of the wire of the electro-magnet, and therefore a
current flows from the battery over the electro-magnets and through the coil of
As the armature
the connected relay to the earth. Both attract their armatures.
lever of the main magnet rests against the contact, it closes a second current
circuit from the battery which branches over the levers of the other three relays
and through the electro-magnets of the hook switches of the three unused speak-
ing places and as these armature magnets attract their armatures the respective
speaking places are locked or bolted so that they cannot be used. The movement
of the lever of the main electro-magnet also causes a spring to be lifted off its
contact so that the call which may be arranged at any one of the speaking places,
is disconnected. By the movement of the lever of the one relay, the wire of speak-
ing place II is connected with the main wire so that this speaking place can com-
municate with the exchange or central office.
The means for switching on the call may also be employed in the switch
arrangement herein before described, and vice versa, the means 'for throwing into
action the call herein before described between the lever and the contact may also
be employed in the switch arrangement just described. In order to give a visible
signal when the line is used, a signal disc may be attached to the lever, which
allows the word "engaged" to appear behind a small aperture or window when the
speaking place is bolted or locked.
Datad this 9th day of February 1897.
"Improved Telephone Systems for Common or Party Telephone Lines,
and Switch Devices for use therein."
I, JULIUS HENRIK WEST of 3 Monbijou-Platz, Berlin in the Empire of Germany,
Engineer, do hereby declare the nature of this invention and in what manner the

page_text: ame is to be performed, to be particularly described and ascertained in and by the
ollowing statement:-
This invention has for its object special switch-devices for common or party
telephone lines, that is to say, fines or conductors which may be used in common
by several telephone sets. These switches are characterized by such an arrange-
ment, that, whilst one telephone set is being used, the switching on of the other
sets into the wire is prevented either by bolting or locking the hook-switch, or by
bolting or operating another suitable interruptor of the speaking circuit of the
unused telephone sets. The arrangement is in general such that only one of the
telephone sets connected with the wire can be called from the central office.
In the accompanying drawings, 'two modifications of switching devices compris-
ing the present invention are illustrated by Figures 1, and 2, both being diagram-
matical views.
For the purpose of description, it will be assumed, that there are four telephone
sets, which will be referred to as I, II, III and IV. These four sets are connected
up in parallel by means of branch wires 12 with the main double wire L' L³,
running to the exchange or central office. The apparatus employed differs from
that of ordinary telephone sets merely in that the call-ball is omitted, whilst an
electro-magnet e, is inserted, the armature lever h, of which is arranged to serve
as a bolt for bolting or fastening the lever of the receiver-hook-switch when attached.
The said receiver-hook-switch is also provided with a special contact 6. Only one
of the sets (in Figure 1 set I) is provided with a call-bell W, which, however, is
not thrown into action in the ordinary manner, but is connected through the
armature-lever h, of the electro-magnet e, and through its back-contact 7, with the
two speaking wires leading to this set I.
The actual speaking and calling apparatuses of the four sets need not be
described, as they are non-essential for the explanation of the present invention.
It will be sufficient to state, that these apparatuses are inserted between the clamps
or terminals 3 and 4 and that the circuit between these two terminals is inter-
rupted when the receiver is suspended on the hook, as shown.
If it be desired to utilize one of the sets, the receiver of this set is first taken
On lifting off the receiver, for
from the hook and then a call current sent.
instance of set II, the lever h of the hook switch will be laid against the upper
contact 6, whereby the' wire is connected to earth. A current therefore flows
from the battery B, through the relay E, the electro-magnet of which will attract
its armature, thereby causing a current from the battery B, to pass over contact c²,
lever H, and wires which lead to the several telephone sets I, II, III and IV
and through the electro-magnets e of said sets, hereinbefore described, which
electro-magnets, accordingly, will attract their armatures and thus lock the hook-
switches of the sets I, III and IV, not in use, while in set II, which is being used,
such locking is not performed, because the switch-lever of this set is already out-
of engagement with the bolting-lever h, of this set. In set I, by the movement of
the locking lever h, the call-bell W is also cut out. By this incans set II can use
the line, without the other sets being able to hear or interrupt. When all the
receivers are suspended on the hooks, the call-bell W is always connected with the
line, so that, thereby, set I may be called from the office.
Figure 2 illustrates a modification of a switching device based on the same
invention, but differing somewhat in details.
According to this modification, the switching on of the telephone sets into the
double wire L'L' leading to the exchange or central office, is performed by means
of relays R1, R2, R3, R4 whereby one of the former four wires may be omitted as
superfluous. The speaking and calling apparatuses as in the preceding example
are connected with wires 1. The telephone sets have no call-bell and when the
receiver is suspended on the hook, the circuit, between the clamps or terminals 2
5. and 3, to which the wires 11, 12 are leading is interrupted.
When the receiver is hanging on the hook, the electro-magnets e of the various

page_text: sets are connected to earth through the contacts 8. If the receiver, for instance
of set II, be taken off its hook, in this set II the wire is connected to earth,
instead of the electro-magnet, and therefore a current flows from the battery B
through the coils of the electro-magnets E and R² to earth. Both attract their
armatures. As the armature-lever of E rests against the contact c³, it closes a
second current-circuit of the battery B which circuit branches over the levers of
the other three relays R, R³ R and through the electro-magnets e of the three
unused sets I, III, IV, which magnets c, in attracting their armatures, lock or
bolt the respective sets so that they cannot be used. The movement of the lever
of the electro-magnet E also causes the spring a to be lifted off its contact c³, so
that the call-bell W which may be arranged near any one of the telephone sets,
is cut out of the line. By the movement of the lever of the one relay R³, the
wire, from set II is connected to the main wire L³, so that this set II, can now
communicate with the exchange or central office.
The means for switching on the call-bell shown in Figure 2 may equally be
employed in connection with the device shown in Figure 1 and vice versa, the
means of connecting up the bell shown in Figure between the lever hand
contact 7 may also be employed in the switch-arrangement just described. In
order to give a visible signal when the line is used, a signal-disc may be attached
to the lever h, which allows the word engaged to appear behind a small
aperture or window when the telephone set is bolted or locked.
"
"
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. A switching-device for common or party telephone lines, so constructed and
arranged, that, whilst any one of the telephone sets connected to the common line
is being used, all the other sets connected to the same line are electrically bolted or
locked in a manner to prevent their being simultaneously switched onto the
common line.
2. A switching-device for common or party telephone lines, so constructed and
arranged, that, whilst any one of the telephone sets is being used the speaking
circuit of all the other telephone sets connected to the common line is electrically
interrupted inside or outside of the said telephone sets, thereby preventing the said
telephone sets from being simultaneously switched onto the common line.
relay,
3. A switching-device for common or party telephone lines, so constructed and a
arranged, that, whilst any one of the telephone sets is being used, all other tele-
phone sets connected to the common line are prevented from being switched onto
the common line, said object being obtained by the receiver switch
hook of the set in use, which, on the receiver being lifted, closes
a relay common to the totality of the telephone sets, which
by attracting its armature, closes a second circuit, containing auxiliary
electro-magnets inside or outside of the telephone sets and connected
parallel or in series, the said electro-magnets operating, by attracting their
armature, to interrupt or to keep interrupted the respective speaking circuit within
or outside of the corresponding telephone set.
4. A switching-device for common or party telephone lines, so constructed and
arranged, and with only one of the telephone-sets which are connected to the line
provided with a call-bell, that on any one of the telephone sets being used, all
other sets are prevented from being switched onto the common line, the call bell
being so connected, that, on any one of the receivers of the telephone sets being
lifted, the said call-bell is electrically cut out.
5. A switching-device for common or party telephone lines, so constructed and
arranged, and with only one of the telephone sets which are connected to the line
provided with a call-bell, that on any one of the telephone sets being used, all
other sets sic prevented from being switched onto the common line, the call-bell, 5
on any one of the receivers of the telephone sets being lifted, being cut out of the

page_text: common line through the medium of a relay common to all telephone sets and
through which relay a current flows as long as one of the telephone sets is being
used.
Dated this 8th. day of November 1897.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.