An Improved System or Method of Arranging Telephones and Appliances in connection with the same, by which thes Re either for Calling for, or Notifying the Completion of Communications to, the Different Subscribers, are Sent Auto- matically.
Year: 1894

page_text: Date of Application, 29th Aug., 1894-Accepted, 20th July, 1895
COMPLETE SPECIFICATION.
An Improved System or Method of Arranging Telephones and
Appliances in connection with the same, by which the Currents
Required either for Calling for, or Notifying the Completion of
Communications to, the Different Subscribers, are Sent Auto-
matically.
I, GEORG RITTER, Telegraph Inspector, of Stuttgart, in the Empire of
Germany, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement and accompanying drawings, that is to say :-
The improved arrangement of the telephone system which forms the subject of
the present invention is such that by taking down the telephone for use and by
hanging it up again, when the conversation is concluded, the connections act
automatically at the place of exchange the currents which effect this action not
being provided at the different subscribers' places but at the exchange station.
The accompanying drawings are in illustration of the invention.
To enable the subscribers to call for a change, all the separate conductors (which
may be distinguished as 11, 1, 1, 1,) are joined to one pole of a battery w', to³, at
the exchange station (see Figures 1-8), the other pole of the circuit is connected
either with earth or with the conductor ¹ (or 2, 3, 4) which passes as a second
conductor to the different places or stations of subscribers. At these latter the
first named conductor is led to the pivot of a changing lever h¹ (or h³, h³, leª‚)
which serves as a hook to hold the telephone f¹ (or ƒ³, ƒ³, f',); the other according
to the method of working selected is either joined to the cut-off switch
(or 2, 3, 4), (Figures 1-4, 7 and 8) or to the calling switch a¹ (or a³, a³, a¹)
(Figures 5 and 6); to a third contact of this changing contrivance the telephone fi
(or f, f³, 1), is connected. By means of this method of arrangement every
subscriber is able to connect his speaking place with the exchange station, either
through a complete metallic circuit, or through one metallic conductor, the earth
being utilized to complete the circuit, it being thus at all times in the power of the
subscribers to close the circuit from wo¹ w³ of the exchange station which is
connected to the conductors, this causing their calling lever (or k³, k³, k¹),
to drop.
To cause the closing levers or contacts d¹ (d², d³, d), (which have been omitted
in Figures 1-6 to make the latter more distinct) of the separate, places of
subscribers, to fall after the conclusion of the conversation, the following arrange-
ment is used.
If the so-called two-wire system (as used in Figures 1 to 6 and 14 to 18) is
employed, a battery (or, i, i) is placed behind each closing lever d', (d², d³, d³),
the current from which is passed through an electro-magnet above the closing
lever, so that the latter, or an armature connected to it, is attracted, and held by
the electro-magnet, and completes the circuit until the current is again interrupted
by the two communicating subscribers hanging up their telephones to their
changing lever, when the closing lever once more drops. With the so-called single-
wire system (used in Figure 8) the conducting wires from the regulating plugs n'
(or n², n³, n'), are branched off, before the electro-magnet of the calling lever k,
from each subscriber's conductor, the latter being only led to a metal ferrule
fastened to the lower part of the handle, or socket, in which the moveable
connecting stud fits, through which the former, by means of the metallic seat of the

page_text: stud or plug, is connected with the calling circuit ', w³, of the exchange station.
As long as the connection lasts the calling lever (or 12, 1, 4), is insulated on
one side. According to the method of working used, the closing levers with their
actuating currents either lie in the circuit passing through the stud or plug, or,
with complete circuits, between the two stud-conductors, or, when using the earth
as return conductor. between the conductor and earth; further details will be
explained hereinafter. This telephone system, as described, can be applied to the
following methods of working :—
-
a) Calling to the exchange station by the subscribers, using the earth as a
conductor; or calling the subscribers through the exchange station, as also
speaking by means of a continuous circuit conductor (see Figures 1-4).
Calling to the exchange station by the subscribers by the use of a continuous
conductor; or calling the subscribers through the exchange station, as also
speaking by means of a return current through earth (see Figures 5 and 6).
c) Calling to the exchange station by the subscribers, as also speaking by means
of a return current through earth; or calling the subscribers through the exchange
station by means of a continuous circuit (see Figures 1-4) in which only one change
is made, namely, that in the place of a conductor leading from the telephone 1
(or ff) to the second return conductor 1, (or 2, 3, 4), a conductor joins the
earth-current. This arrangement is indicated in Figures 1-4 by dotted lines.
With all these three ways of working the following arrangements of conductors
can be applied :-
1. Each speaking place may have a separate second metallic return wire.
2. For certain groups of speaking places, the same return conductor may be
utilized.
3. For all speaking places a common metallic return conductor may be used.
4. Under the method of working described under a aud c, a fourth arrangement
of conductors is possible, which consists in joining together a certain number of
subscribers' conductors behind the speaking places, so that according to requirement
a part of the conductors, thus connected, can serve as a return metallic conductor
for one or more of the others, instead of the special conductors 2', (or 23, 2³, =³),
which lead back to the exchange station..
For working the telephone-system described, changing switch boxes can be used,
for single as well as manifold working, also as calling source of current a constant
current can be used, as well as an alternating one. The action produced by the
different methods of working and the different arrangements of the conductors,
will be described below, reference being always had to the illustrating figures. To
make the description as clear as possible the movements required to be made by a
subscriber or an employé at the exchange station to produce a connection, will be
followed.
A. CALLING TO THE EXCHANGE STATION BY A SUBSCRIBER.
This is done, in all the above-mentioned systems of working and arrangements
of conductors, by the subscriber taking down his telephone (or f³, ƒ³, f'), 'from
the hook on the switch lever (or h,, ); by this action the latter is raised by
a spring or weight (neither of which is shewn in the drawings as being unimportant).
By this means the lever, being made of metal, comes into temporary conductive
contact with the calling-circuit closer a' (or a³, a³, a',); as long as this connection
continues the calling current from w', u' of the exchange station remains closed,
which causes the dropping of the annunciator or contact-maker, ', (or k², k³, h³), of
the same subscriber. The direction of the current, indicated by free arrows, is as
follows:-
1. With the conductor-arrangements 1, 2, 3 and 4, of "the working systems
described under a and c (see Figures 1-4), from the main conductor b', b',
and 2, 3, respectively into the conductor (or 1, 1, 1), round the electro-magnet
of the calling contact-maker k- (or k³, k³, k*), to the switch lever h³, (or h³, h³, h*)

page_text: and from thence over the closer of the calling current a' (or a³, a³, a¹), to the
earth and through this back to the other pole of the battery w³, 10³.
e
2. With the conductor-arrangements i, 2, and 3 of the working systems
described under b (see Figures 5 and 6), from the main conductors 6', b', and b³, b³,
respectively exactly as in 1 to the closer of the calling current a¹, (or a², a³, a²) and
from this through the return conductors z¹, (or -³, 23, 4) to the other pole of the
battery w¹.
"
In Figure 5 the working systems 1 and 2 are represented conjointly; if the
latter is desired, the conductors 2³, 23, and a', ', are supposed to be non-existent,
and their place must be taken by those shewn in the dotted lines joining and ²,
as also and ¹. When the single-wire-system is applied the sockets or seats for
the connecting studs or plugs at b', b', and b, b, respectively, take the place of the
main conductors from which the current passes into the conductors l', (or 1, 1, 1),
through the metal ferrules on the plugs or studs, attached to the lower part of the
latter. In Figures 7 and 8 the conductor-arrangements 1 and 4 of the working
system a are represented. It may be mentioned here that the calling battery
has sub-divisions w¹, w³, according to the different resisting power of the con-
ductors. Only in case 3. of, all the working systems a, b, and c, a division of the
current for calling to the exchange station by the subscribers is not practicable
(see Figures 3 and 6), because the subdivision w¹ would be liable to be permanently
closed.
B. CALLING THE SUBSCRIBERS THROUGH THE EXCHANGE STATION.
Before describing this operation it may be mentioned that the conducting
wires (or 1, 1, 1), of the subscribers lead from the main conductors b, b, of the
circuit, first round the electro-magnets of the annunciators, and afterwards through
the changing handles. The latter are so constructed that by placing the contact
studs or plugs into them an interruption of the subscriber's conductor (or 12, 13, 14),
to the calling circuit n', (or n*, nº, n), takes place, either by means of the handles
themselves, or through the closing of a supplementary circuit in which is an electro-
magnet the armature of which, in its attracted position, interrupts the subscriber's
conducting circuit (see Figures 12 and 13). The details of both these arrange-
ments will be described later on, as well as those of the contrivances for calling
the subscribers through the exchange station.
In the first place, it will be shewn, aided by Figures 1-8, which conductors
must be connected by the employés at the exchange station to enable them to call
a subscriber. Figure 1 (conductor-arrangement 1 of the working system a and c).
Supposing that subscriber 4 is to be called; his conducting-wire belongs to the
shorter ones, and therefore the whole current from 101, 10 is not required for calling
bim, but only a part of it. For this purpose the pole connected with the earth, of
the battery w', w³, is joined to the conductor 1, and the corresponding second
conductor z to the main wire b², b. The connecting conductors are represented
by dotted lines, the arrows at their ends represent moveable connecting handles or
plugs, the dots on their other ends represent permanent connections, the current is
iudicated by arrows, and goes from the conductor &,, through the conductor,
the bell 9, closer of current to the latter when the telephone is not in use,,
changing lever, and through the conductor back to the same part of the
battery w. If a subscriber, haying a longer conductor, is to be called; his second
conductor z must be joined to the conductor 6, 61, so that the whole battery i¹, w³,
comes into action.
Figure 2. (conductor arrangement 2 of the working system a and c). Supposing
that subscriber 3 has to be called, for this purpose the exchange station employé
connects the conductor, which is separated from the calling battery w!, w; with
the pole of the latter, which.is.connected to earth; also the second conductor ', 21,
with the main conductor b', b, so that the. following course of the current is
produced-From the conductor, b', 6' the current passes through the secon

page_text: conductor, to the bell g, the closer of the current to the latter when the
telephone is not in use, through the lever and the conductor over the
moveable stopper contact maker, back to the battery. The conductor belongs to
the longer ones but when the call is to be sent through a shorter line, a connection
must be made between 2, 12, and 22, 22, so that only the part w³ of the battery is
used. Figure 3 (conductor arrangement 3 of the working system a and c).
Unlike the calling by the subscribers to the exchange station, when the battery
must only be used undivided, in this case the subdivisions of the battery current can
be used for calling. If, for instance, the subscriber 3 is to be called, a connection is
made between 3 and the earth pole of the battery, w¹, w², as also between the
conductor and the second conductor, which causes the current to take the
following course :-
From the conductor b', b', over the second conductor z, z to the bell g³, closer of
curient to the latter when the telephone is not in use, r³, lever ³, conductor ³, and
over the moveable plug contact to the battery w¹, w². If one of the shorter con-
ductors is to be used for calling, a connection is made between 1 and a point
between w¹ and w² of the calling battery w', wo, by which only the part w¹ of the
latter is made use of. Figure 4 (conductor arrangement 4 of the working system a
and c). To call a subscriber it is only necessary to effect a temporary connection
between the conductor of the subscriber who is to be called, and the earth pole, of
the calling battery ¹², then only the necessary part of the battery comes into
action. This connection is shewn for subscriber 5, and the current takes the
following course:
From the conductor through the other subscribers' conductors joined to it,
to, the connecting wire c, c, thence through the belly, the closer of current to
the latter when the telephone is not in use, 78, lever, conductor and the moveable
stopper contact back to the battery w w³, of which only the part w³ is made use of.
If for subscriber 3, the whole battery is made use of. Over the other subscribers'
places in the group referred to, the current passes in the contrary direction, as
described for the subscriber's place 5, the bells of the same being so constructed
that they only operate either with the full current, or with a current coming in the
contrary direction.
Figure 5 (conductor arrangements 1 and 2 of the working systein b):
The method of calling by the subscribers through the exchange station 18 the
same as with the conductor-arrangements I and 2. If, for instance, subscriber 4 is
to be called, a connection is made between conductor and the main conductor b², 62,
so that the following is the course of the current :-
.
From conductor to earth, through earth to the subscriber's place 4, and
thence through the bell g', the current closer to the latter when the telephone is not
in use, ', and lever , to the conductor 14; from this through the moveable plug
contact to the conductor 663 and back to the calling battery w¹ this part alone
coming into action. If, in calling through a long conductor, the whole current w¹ w
is required, a plug is used by which connection between 4 and 63, 6³ is made.
Figure 6 (conductor arrangement 3 of the working system ):
In this case the same connections are required to call the subscribers through the
exchange station as in Figure 3. If, for instance, subscriber 3 is to be called, the
current passes through conductor to earth, through earth to the subscriber's
place 3, thence through bell 93, current closer to the latter when the telephone is
not in use, 3, lever to conductor 3, thence through the moveable plug contact
to the battery w' w the whole of which comes into action.
When calling through a shorter conductor, only the part wl comes into use, as
the moveable conducting plug then makes a connection, between to and, w².
Figure 7 corresponds with the conductor arrangement 1 of the working system a
applying the single wire system.
.
In this case, the connections are so arranged, that subscribers 2 and 3 are called.
In Figure 7 the earth pole of the battery w w is connected with the conducting
wires 1, 3, and the return wires ³, 2, by the plug,-according to the length of the

page_text: subscriber's wire (z' for instance), the longer wire to the pole of the entire
battery ww, with the return wire, and the shorter wire to the part w³ only.
These connections are shewn in dotted lines. The current, as shewn by the
arrows, passes from the pole of the entire battery w¹², or from the pole of the
part only, through the wire or 3, beli g', or g, the closer of current t
the latter when the telephone is not in use, or ³, lever or h³, and conducting
wire or 1, which pass together to the other pole of the battery.
Figure 8 illustrates the conductor-arrangement 4 of the same working system,
but with the application of the single-wire system. In both cases the connection,
are made in such a way that subscribers 2 and 3 are called, the course of the
currents requiring no further explanation, as the descriptions of Figures 1 and 4
can be referred to; it is only necessary to mention that to the connecting
conductors c', e¹ as also ², e, not two only (as represented) but more subscribers'
conductors may be joined which serve as second conductor for the current of the
subscriber's conductors 2 and 3. The above descriptions give all necessary
connections of conductors, for the different conditions for calling subscribers
through the exchange station, and the following will explain the manipulations
which enable the exchange employé to make the above-mentioned connections,
in a quick and simple manner. In Figure 9 are represented the contrivances
required by the conductor-arrangements 1 and 2 of the working systems a and c
(see Figures 1 and 2).
Of the two moveable connecting plugs or handles, which are brought into
use, one serves to connect with the calling person, and the other to call the
subscriber who is asked for; the connections between the battery wl, w³ and the
conductors (or 12, 13, 14), and 2¹ (or 22, 23, 2¹) are represented by dotted lines;;
the former connected with the earth pole of the calling battery w², w³, is necessary
for calling through any of the conductors, whatever their resistance may be, the
connections with the main conductor 6, having only to come into action when
the call is to be made through a subscriber's conductor of great! length, those
with 6, for a call through a short conductor. To make this possible, connecting
conductors from the battery are taken to the handles or sockets of each subscriber's
moveable plug or circuit completer, and the handles are supplied with springs,
and according to the resisting power of these springs the connecting conductors
are joined either to b', 6', or to b, 6. In the first case the full battery power w', to²
comes into action, in the second case only part of it. The procedure used in calling
is as follows: -
1. Working system a, conductor-arrangement 1 and 2. When by inserting the
plug the number of the subscriber who is to be called is made known to the
exchange employé, plug II is put so deeply into the handle or socket of the number
asked for that the spring touches the metal piece 6 of the plug, and the spring p,
is pressed against the spring 2, through which the course of the current, as
indicated by the arrows and described above, is determined. On releasing the
plug this latter is automatically pressed into the speaking position by the
spring 4.
2. Working system c, conductor arrangement 1 and 2. By placing the ringing
plug IV into the handle or socket, corresponding with the subscriber who is to be'
called; the spring comes in contact with the metal piece 14, and the springs z and p'
with the metal piece 16 through which the current takes the same course as above.
It may be mentioned here that the contrivance used with plug IV to cause a'
temporary metallic connection between springs p and z, can also be applied to the
plug II and vice versa. (Cases a and c differ only in so far that in the latter a
single wire conductor is used for speaking, in the former case a complete metallic
circuit.)
In Figure 10 the calling contrivance for the conductor arrangement 3 of the
working systems a and c is represented, the course of the current being indicated
by arrows, the way in which it is produced will be easily understood from the!
description already given. To produce a call with the conductor arrangement 4°

page_text: of the working systemns a and c it is necessary to establish a connection between
the conductor of the subscriber who is to be called and the earth pole of the
hattery w¹, w (see Figure 4). Therefore in case a the conductors p', p¹, p², p³, with
the springs belonging to them, can be dispensed with (see Figure 9, stopper 1I),
whilst in case even the spring can be omitted, because the speaking is done
bere by a single conductor. (Figure 9 stopper IV.) A more detailed description
is unnecessary, and it is sufficient to add, that in case the ringing by means of the
plugs is not desired, ordinary ringing keys can be used. The calling contrivance
required for working system b conductor-arrangement 1, 2, and 3, is represented
in Figure 11, in all three cases, the object is to produce a temporary connection
between a subscriber's conductor and, according to the length of the latter, and
its relative resistance the whole, or a part of the battery w', w (see Figures 5 and 6).
For this purpose the springs p of the subscribers' handles or sockets are joined
to the conductors 63, 62 or 3, 6, according to whether these subscribers' conductors
are shorter or longer. The calling is done by inserting the plugs II and IV into
the handles of those subscribers who are to be called.
The production and the course of the current require no special explanation,
after what has been already said. When the calling by the subscribers is done
through the exchange station, by means of the full, current from w', wo³, only, and
not by means of subdivisions of the same, which may be done with small systems,
where the difference of resisting power in the subscribers conductors is small, or
when working with alternating current, then the calling springs p in the plug
supports or handles of the subscribers can be dispensed with, or ordinary electric
bell connections can be used. There remains now to describe the contrivance,
above referred to, for separating the conductors of the subscribers from the
battery.
In Figure 12 the contrivance is indicated by which this separation takes place
in the handles or sockets themselves; 1, 2, and 3 are intended for the springs in
the handles of a double conductor, 4 and 5 for those of a single conductor; in the
position of repose, 1 and 2, or 4 and 5 respectively, touch each other; but when
a plug is inserted 2 and 3, or 5, are pressed sideways, so that separation between 1
and 2, or between 4 and 5 takes place.
An electro-magnetic contrivance for separating is represented in Figure 13,
where the supplementary circuit which is used with the electro-magnet e and
battery is connected one way with the handle-sockets and the other way with
the plug-ferrules z. As soon as a plug is inserted into a socket a closing of the
circuit takes place, and the electro-magnet e interrupts, by attracting its armature, «,
the conductor l.
-0.
PRODUCING THE CONNECTIONS BETWEEN TWO SUBSCRIBERS, AND THE
METHOD OF INSERTING THE CLOSING LEVERS TO CAUSE THE
AUTOMATIC PRODUCTION OF THE SIGN OF CONCLUSION OF SPEAKING.
The speaking circuit produced by the conductor-arrangement of the working-
system a, in the connection of two subscribers' conductors is illustrated in Figure 14ª,
in which the dots 1 and 2 represent the springs of the handles or sockets of. con-
ductors and 1, 3 and 4 those of the conductors and . Here the closing-lever
or contact-maker d with the battery belonging to it, can be inserted either
between the two plug conductors 1-3 and 2-4 (see Figure 14^) or else in one of
the two latter, in which case it is indifferent in which the contact lever and
battery are placed, (sce Figure 14B). It must only be noted that. in the first case
the interruption of both subscribers' lines is necessary to cause the dropping of the
levers or contact makers, whilst in the second case the interruption of one of the
two subscribers' conductors is sufficient for this purpose.
In Figure 15 the method of connection between two subscribers' lines for the
nment off of the wauki
camo ciens

page_text: must be inserted in the plug conductors circuit; and according to Figure 15ª,
either between the dots 1 and 4, or 2 and 3. On the other hand the insertions
according to Figures 15" and 15° are not admissible for the following reasons:-
In calling to the subscriber's place through the exchange station the conductor 6,6
with second conductor :', ', and conductor, with second conductor, ³, must
be temporarily connected; if the contact lever is inserted in the plug conductor
circuit between the dots 2 and 4, 1-3 closes the current o abruptly, and the same
with insertion according to Figure 15°; if, however, the lever is inserted in the
plug-conductor circuit 1-3 (see Figure 15B) or according to Figure 15" between
both plug-conductors 1-4 or 2-3, then both subscribers' conductors and can
be interrupted without causing the contact lever to drop, in the case of two
subscribers of both groups being called; whereas by the insertion according to
Figure 15, such dropping must always take place as soon as both conductors
and are interrupted. The insertions which are admissible for the conductor-
arrangement 3 of the working-system a are represented in Figures 16 and 16B,
whereas Figure 16° represents an insertion that is not admissible. In Figure 164
the contact lever d with its battery lies in the plug-conductor line 2-4, which
connects the conductors and with each other; their placing in the line 1-3 is
not admissible, as can be easily seen. In Figure 16 the lever and the battery
belonging to it, lie between the two plug-conductor lines 2-4 and 1-3; both
ways show practicable insertions, whereas according to Figure 16", an automatic
dropping of the contact lever could not be effected with such an insertion. In
Figures 17 and 17" two insertions are represented which must be considered in
reference to the conductor-arrangement 4 of the working system a; the first figure
requires no further explanation. With the second, permanent closing of the circuit
through w', w over the joined conductors and the contact lever takes place which,
under some circumstances can be used to replace the battery i, because with the
interruption of the conductors the above-mentioned permanent closing ceuses As
with all conductor-arrangements of the working systeins b and c, the speaking takes
place through a single conductor, using the earth as a second or return conductor,
the insertion of the contact levers d with the batteries i belonging to them, must
be considered as they are represented in Figures 18 and 18B. These insertions
require no further explanation after what has been already said.
ni
There are still to be mentioned the two cases of the single-wire system
represented in Figures 7 and 8. In the case of Figure 7 (conductor-arrangement I
of the working-system a) the contact lever and the battery (or i,,) are
inserted in the plug-conductor line n', (n³, n³, n') the insertion of the same
between n¹, (or n³, n³, n'), and the second conductor 2, z is not admissible because a
permanent closing of the current from ' (i², i³, 1) over the subscriber's place
belonging to it would take place.
In Figure 8 with conductors 1 and 2 the contact lever d' (or d³, d³, d), with its
battery (or, 3, ') is placed in the plug-conductor line n', (or n², n³, n¹) (as in
Figure 18), whilst with the conductors 3 and 4 they are between the plug-
conductor, (or n³, n³, n³) and the earth (as in Figure 18"), here also the
battery (or, ) is replaced by the current through.
To ensure the safe falling of the contact levers d' (or d', d³, d'), and to prevent
a repeated falling of the contact levers k¹ (or k², k³, ), the circuit closer a of the
subscribers' places is made in such a way that by the receding of the lever h¹,
(or h, h, ), when the telephone is again hung up, the current is not closed or
completed. This is effected (see Figure 19) by a spring which is attached to the
lever h, and the piece a which closes the circuit is so formed that in raising the
hook h, the upper, metallic surface of a is touched by the spring a, but in dropping it,
the lower, non-conducting surface comes in contact with the spring which is
attached to the lever h.
1
Finally, the insertion of a subscriber's place as represented in Figure 20 remains
to be mentioned; this differs from those represented in Figures 1-8, through the
bell g being inserted in the conducting line l, instead of being in the second

page_text: :
Conductor z, by which means the bell is made to ring when subscribers call to the
exchange station.
During the speaking the bell is quite closed. If it be desirable to omit the
'speaking contacts and s¹ the telephone can be permanently put between the
conductors and 2, or between land earth respectively, but in this case considerable
1esistance must be given to the telephone fin proportion to the bell I.
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 1 claim is :-
1. The improved telephone system, in which no special currents are necessary,
either for calling to the exchange station or for giving the concluding signal at
the places of the different subscribers, both above-named signs being given auto-
ma ically, such system being characterized by:
The subscribers' places being connected with the exchange station through
conductors 1, 1,,, which, at the subscribers' places, are provided with devices
which, besides inserting into and cutting out from the speaking circuit, the aların g
and the telephone f, cause the calling or the concluding signal respectively, at the
exchange station, there being also provided an alarm g; at the exchange station,
the handles or sockets, the calling device k, as well as the common battery w¹, 20³,
the currents from which in the position of repose are broken, according to the
manner of working chosen, either at the exchange station or at the subscribers'
places, when one of the ends of the connection is connected with earth, and the
other is insulated, it being further possible to use the insulated branch of the
connection for several subscribers conjointly; further, the conducting plugs or
handles serving to connect the subscribers' conductors, circuits being so formed that
they close the currents through the electro-magnets of the contact levers, used for
these connections, through the respective speaking circuits, as long as the speaking
lasts, and the holding of the turned-back contact levers continues, until by the
hanging up of the telephones f by the connected subscribers to the lever-serving
as hook of the above-named device an interruption of the speaking circuit takes
place, and with it an interruption of the current passing through it so that the
contact-lever, being set free, falls.
2. The method of operating the improved telephone system described in Claim 1,
by means of changing switches or devices in combination with circuit closing
springs in the handles or sockets of the conductors, through which communication
with the different subscribers is effected, the springs, being so connected, with the
calling battery current of the exchange station that, by properly placing the con-
ducting plugs into the handles or sockets, a part of the current comes into temporary
action, such part corresponding with the resistance of the subscriber's conductor in
question, in order to call the subscribers by means of a metallic connection between
the said circuit-closing springs and the handle-springs attached to the subscribers'
conductors.
3. The method of operating the improved telephone-system described in Claim 1,
by means of changing switches or devices inserted in a single wire system, in which
a conducting wire n, n, regulated by a plug, branches off from the subscribers'
conductors 1,1, before the calling device, such conducting wire being connected with
the contact lever d, and with a battery connected with it, in the manner described
under Claim 1.
4. The method of operating the improved telephone-system described in Claim 1,
by means of such an arrangement of the subscribers' conductors that the branches z, z
of the conductors are not connected with the exchange station, but only with the
insulated wires c³, c', c², c², groups of conductors being formed, so that a part of the
conductors of these groups can serve, according to requirements, as metallic return-
conductors for the remaining ones.
5. The method of operating the improved telephone-system described in Claim 1,
by the use of switches, by which the contact levers are inserted in parallel circuit
with the calling devices of the subscribers' conductors which are connected with

page_text: each other, in combination with the contrivance for an automatic interruption of
the subscribers' conductors for the purpose of separating the latter from the calling
batteries w¹, 20³.
6. The method of operating the telephone system described in Claim 1, by the
use of single speaking conductors which are supplied with handles or sockets at the
exchange station, these handles or sockets containing only a current-closing spring
(as illustrated in Figure 13) so that interruptions in the subscribers' conductors do
not occur in the handles or sockets, and when connections are made between two
subscribers' conductors, the circuit of the contact lever is parallel with that of the
calling device, in the connected subscribers' conductors.
Dated this 28th day of August 1894.
EDWARDS & Co.,
65 and 66 Chancery Lane, London, Agents for the Applicant.