IMPROVEMENTS IN APPARATUS FOR TELEGRAPHIC AND TELEPHONIC COMMUNICATION
Year: 1883

page_text: LETTERS PATENT to Otto Schäffer mechanician of Vienna (Austria) for
an Invention of IMPROVEMENTS IN APPARATUS FOR TELEGRAPHIC AND
TELEPHONIC COMMUNICATION
COMPLETE SPECIFICATION filed by the said Otto Schäffler at the Office of
the Commissioners of Patents on the 23rd June 1883.
OTTO SCHÄFFLER, mechanician to [of] Vienna (Austria) IMPROVEMENTS IN
APPARATUS FOR TELEGRAPHIC AND TELEPHONIC COMMUNICATION
In the practical telegraph service it frequently appears desirable and often
necessary, to call, from among the stations connected in a partial circuit, the one
only for which the message is intended, without alarining the others and thus to
deprive them of the opportunity of disturbing the calling & the correspondence
when once begun and of reading the latter or noting it in any other way. For
telephone lines, especially when they effect the connection between the separate
stations by means of telephone exchanges, an appliance making the above said
possible would be most valuable and particularly so because it would allow, in
opposition to the system at present in use, of connecting several stations in one
circuit, and thus not only diminish the primary expense of the lines, but also that
of their working, in a very great measure.
All these different objects can be attained by enabling every telegraph &
telephone station to turn an adjusting plate provided with the name and number
of the station so as to send electric currents of a certain direction and minimum
duration into the line, which currents bring polarised relays and these again
electro-magnets into function, which latter by means of lifting pieces fastened to
the armatures turn contact plates and thus, continually answering the intention
and aim, effect turnings of theso plates which keep in exact pace and action with
those of the adjusting plates.
As by a full turn of the adjusting plato so many emissions of current take
place as there are stations connected with the line, but as the contact plates are

page_text: only in two positions, viz: the normal and the one corresponding with the name
and number of the station, in connection with the conduit, it is clear that the
calling station by turning the adjusting plate connects and disconnects one station
after the the other, & that only the station whose name and number are indicated
by the plate can & will be connected.
The electric currents used for making signals or signs are opposed in direction to
those mentioned above; they will not therefore bring the aforesaid polarised relays
into function, but the second relays and through them the signal alarums or
correspondence; but as only the calling stations and those called upon are alone in
connection, they only can exchange these signals, signs or sounds.
The first movements of the contact plates raise closing bolts, which close the
adjusting plates by mechanism & consequently no interruption of the corre-
spondence can take place, as any attempt to turn the adjusting plates and therefore
also the contact plates is prevented. Finally the inductive actions, which arise in
the multiplicator coils of electro-magnetic apparatus during the passage of the
electric currents, which increase in direct proportion to the windings of the wire
and exercise such a weakening influence on the re-delivery of the voice, that it has
not been found good to connect several telephone stations in one line, without
materially impairing the functions of the receiving apparatus are thereby removed
or reduced to such a minimum, that the alarums being necessarily apparatus with
coils of little resistanco but of numerous windings, are disconnected at the stations
not taking part in the correspondence.
Material Requisites and Arrangements.
1. For every Tolegraph Station
furnished with apparatus of any system whatever, a polarised relay represented in
top view by Fig. 1. whose armature lever b by means of the pole stands a u²
and the adjusting screws c c¹ is so fitted in, that when in normal position it always
touches one certain adjusting screw c' and is laid against the contact and adjusting
screw c only during the emissions of currents and by.then alone.
Further a common connector, consisting of a transmitter and two receivers or
instead of it any exchange system whatever which allows one point to be
alternately connected with two other points.
11. For every Telephone Station
two polarised relays, Fig 1 or a polarised relay with two armature levers, seo top
view Fig. 2. The two armaturo levers b, b¹ which in consequence of armature beds
fixed on the opposite poles ns are polarised in opposite ways, are so fixed by the
pole stands a a¹ and the adjusting screws c c and cc, that in their normal
condition they rest against certain adjusting screws c¹ c³ and are only laid over to
the adjusting and contact screws c c² in consequence of emissions of currents in
certain directions and only while they last.
According to the above said it is clear, that each of the two armature lovers
answer only one direction of the current, but otherwise is always and after each
emission of current will be in the normal position and therefore that this relay
fulfils the functions of two relays with an armature lever each.
It is evident, that the constructions (represented by Fig. 1 and 2) of the
polarised relays can be replaced by apparatus on the same principle although of
different construction. The relays can likewise be replaced by magnet needles.
III. For every Telegraph and Telephone Station
A key-board or adjusting plate N and a contact plate C Figs. 3, 4, 5 and 6 which
revolve in a common bed a, a', a², a³, a' round the respective horizontal axes bb'.
The adjusting plato No, Fig 5, is provided with so many pins (the drawing
shows 6 ww) as thero are stations connected in the circuit and one more,
indicated in the drawing by w and answering the cipher 0 for the norinal position,
and has on the front side the names and numbers of the statious-in the drawing
the numerals 0 to 5. The contact plate C, Fig 6, has only two pins, of which
one, v, answers the normal and the other v that position which this plate will tako
in the station called and when called. On the front side it is indicated with a
:

page_text: white field a for the normal position, with a red cross in the white field ẞ for tho
position of the station called and with red fields yy for all those positions taken
up by the contact plate, when two stations correspond with each other & the line
is occupied. It is a matter of course that the number of 5 stations selected for the
drawing, is by no means the highest number of stations capable of being connected
in one circuit, but that the number may be varied at will; however in every case
the number of pins on the key board plate must equal that of the stations
connected, exclusive of the one for the normal position. As the proportion of tho
number of the pins increases or decreases so increases or decreases the number of
the lifting and closing wheels.
The axis 6 of the adjusting plate bears the closing wheel cand on it the lifting
wheel d; the axis b' of the contact plate bears the closing wheel c¹ and the lifting
wheel d; the two closing wheels and the lifting wheel d have twice as many
teeth as the adjusting plate has pins, whereas the lifting wheel d¹ has only an
equal number of cogs.
On the back wall of the bed a. a' are the clicks s and s¹ then the bolt frevolving
round fand the contact sheets supports e and h and the contact scrow supports g
and i are fixed insulated.
Above the rim of the adjusting plate N the contact sheet / revolves round tho
axis e screwed into the support e, with the contact spring between the
adjusting and contact screws ; 1 in the mannor determined by the pins w―ws in
the turning of the plate, on the lower side of this sheet and just where the pins
operate, the insulating plate 2 is fixed.
Above the rim of the contact plate C the contact sheet b¹ turns round the axis h¹
screwed into the upright h, and its motion is regulated by the contact pins and v
and the contact screw in such a manner, that the conducting connections v
or are always restored before interruption of the connection and that
inversely the sheet lies on the contact screw k always before the interruption of
the connections vor v. Both contact sheets are permanently pressed
downwards by the coiled springs wound round the axes e² and h¹ as may be scen
in the drawing.
The contact plate C bears besides the stud f¹, which regulates the motion and
position of the click bolt f. The construction and arrangement of the contact screw
supports vis: g with the adjusting screws j and j¹ and i with the adjusting
screw is plainly visible in the drawing.
The motion or turning of the adjusting plate N ensues by pressing down the
key T, whose axis turns at n between the bearings m and a¹. This key, which is
forced back into the normal position by the spring to, consists of a jointed lever tt',
which bears the recoiler regulating the motion of the lifting-piece d, and of
the arm t³ projecting beyond the fulcrum n with the elastic lifting-piece t.
The turning of the contact plate C is occasioned by the motion of the armature o
of the electro-magnet E, which revolves round p, is checked in its motion by the
adjusting screws p¹ p² and regulated by the slide spring o³ and the spring-test o*.
Its arm o' with the elastic lifting-piece o³ gears into the lifting wheel d¹ and its
other arm o regulates the turning motion in such a manner, that by every motion
of the armature the plate can advance by the breadth of one tooth.
IV. Further fittings required:
a. The Telegraph stations should be provided with the apparatus and batteries
necessary for correspondence and of the system therein adopted.
C
b. The Telephone stations should be provided with an alarum (automatic contact
breaker) each, a telephone or microphone transmitter, one or two telephone receivers
suspended from an automatically working connector, 2 keys, which are pressed
simultaneously by one pressure and the necessary current generator either batteries
or inductors. The batteries may be of any system whatever; but the inductors
must be provided with a commutator and a click, which allows the axis of the
armature to turn in one direction only.

page_text: For the arrangement of central telephone exchange the functions of the adjusting
and contact plates are performed by a single plate, which prevents the silencing of
the central and allows of a control of the correspondences at any time. The
constructive design of such an arrangement is, of course, dependent on local
circumstances, and whether an entirely new arrangement has to be made or one
already existing has to be altered.
TT
RC (correspondence relay) o (battery wg && no way) Cb L' e¹ R p¹i Le Ba
in line II
2. Position for calling a certain station :
Connector m w.
The calling station places the connector from w¹ to w and presses the key T so
often, till the name or number of the station to be called is visible at the fixed
place and sends, as often as one of the pins aa, goes through under the sheets
L&L presses on the contact screw 9 the + current over w (o RC c d TC w¹ &
o CbLR p¹ i no way) m v (c' no way B ẞ in line I & the current over T
(g no way) Le Ba in line II. In the receiving Stations the currents travel
as shown in As, but as the direction of the currents sent by pressure of key T is
opposed to that in which key TC sends, the polarized relays will answer and the
armature levers laid against contact screws for the duration of every-emission.
will close the local connections for the electro magnets E. S. (Battery × ES ja
I W Battery) the armatures of the electro maguets ES being set in motion will
turn by means of the lifting pieces the contact plates C to the right, draw away
the pins b, from under the sheets L'; lay these sheets against the contact screws i¹
open the click bolt fT thereby close the adjusting plates so long till the contact
plates have completed a full revolution i.e. till they are again back to their normal
position. In consequence of the connections L. now being restored the Station
apparati are silenced and the currents travel from line I over B. B vi¹ L'. e¹ Rp¹
iLe Ba into Line II.
When the calling station has turned the adjusting plate so far that the number
or name of the Station to be called is visible at the fixed place-in the station
called the contact plate will show the red cross in a white field-it then transfers
the connector from w to w¹ and does the correspondence in the manner described
under a¹.
When the correspondence is over the calling Station transfers the connector
from w¹ to w., brings the adjusting plate by means of repeated pressure on the key
into its normal position then moves the connector on to w¹ again and will then be
as all other Stations (see a) in the normal position.
b For Telephone Stations.
•
The connecting schemes represented in the Figs 8 and 9 differ in so far from each
other as Fig: 8 shows a Station with telephone transmitter and induction systemi
and Fig: 9 one with microphone transmitter and battery system; in all details
they are otherwise identical-In both schemes for the sake of clearness two
polarized relays each with a lever are given of which one is for the electro magnet
turning the contact plate and the other for the alarum. By using the polarized
relays with two armature levers-visible in Fig: 2 the schemes are only in so
much modified as the relays R.p². are wanting the points x d are connected direct

page_text: with each other and the alarum is connected with the local closing of the,
corresponding lever
1. Normal position.
The adjusting plates show o and the contact plates white fields.
Currents entering through line I travel over a B. (electric plate) E Li (contact
sheet and lower adjusting screws) R p¹ (polarized relay) E' L' (contact sheet)
b C. (the contact pin answering the normal position and the contact plate)
U (automatic connoctor) x R p³ polarized relay) d Tr c (combined call or signal
koy) s (Trc' A Tu and: x Batteries 9 no way) o ( TT and M t¹¹ no way);
(il no way) Bẞ into the line II In this position it is possible for overy:
Station connected in a circuit to send intelligible signals to all Stations by
pressing on the keys Tr and Tr¹ and by lifting the telophone receiver.
suspended from the automatic connector to exchange communications with them
(circulars &)
2. Calling position.
If a Station wishes to call a certain station alone so that it only hears tho
communication to be made it pressos and without any further preparation the
key T so often till the name and number of the Station called appear on the
adjusting plate (sce a 2)
It may be remarked hero that the backward turning of the adjustable plato was
choson hero so that the emissions of current effected, by it should have a certain
minimum duration, and therefore it is clear that instead of this manner of motion.
any other method can be employed whether with direct or indirect working cranks
or conduit.
The omissions of current ensue in Fig: 9 by the pressure of the key T, alone;
in Fig: 8 by the simultaneous and repeated turning of the inductor axis and with
the oxception of the calling Station corresponding turnings of the contact plates.
will take place in all Stations.
line I and
-
The calling Station sends in Fig: 8 × currents from Tu over J¹ I. L. E B³ in
currents from T. N. over c¹ Tr¹s (c Trd Rp³ x n c b L' E¹ Rp¹ i
no way) o (TT L'H' no way) v (i no way) B. ẞ in line II, and in Fig: 9
× currents from the battery over J' I. LE Ba in line I and
battery over x c¹ Tr¹ d's or v B.ẞ in line II.
-
currents from the
All other Stations connected except the one centralization station receive theso
currents from line I and let the first emission reach line II in the manner
described in b, but as this first emission of current makes the polarized relays R. pl
answer and therefore lays the armature levers j against the contact screw the
local connections for the electro magnets E. S are thus made Fig: 8 Battery 8 8 j
E. S. J Battery and Fig: 9 battery 8 Jôj E S J battery., so the armature and
lifting piece 5 of the electro magnets E S. come in action turn the contact plates
to the right, raise the click bolt f and lay the contact sheets L' against the contact
screw .
Consequently the following emissions of current will enter by line I and
over a B. 9 Li Rp¹ e¹ L¹ o' v Bẞ reach line II.
This course of current-also for the signal and speaking emissions of current
mentioned in 63 b, is pervading and equal for all stations connected, tho
Station called is connected by the connection L' 6-the pin b¹ answers to the
name and number of the Station called which latter is marked with 3 in the
drawing which connection replaces the normal L¹ 6
3. Position of signals,
The adjusting plate of the calling Station called and the contact plate the white
field; the adjusting plate of the Station called shows o, and its contact plate the
red cross in the white field and in all disconnected Stations the adjusting plates
show 0, and the contact plates red fields The calling Station presses the keys T
and Tr and sends-in Fig: 8 by simultaneously turning the inductor axis and in
Fig: 9 by the pressure alone - : × currents over J₁g Trds or B 3 in line II

page_text: and currents over Tr d Rp
lever 3 against the contact
alaraum g battery 5 g h c
which answers to this direction of current-lays the
plate 62 and thus restores the local closing for the
5 battery-x ucb L¹ e¹ Rp¹ i. Le E. Ba in line I..
In the Stations. not called and consequently disconnected these currents travel
from line I over and Be L³ Rp' e¹ L¹¹B ß into line II
In the Station called the current enters line I at a B and reaches over € Li
RpLCU Rp³, this relay answers and closes as before said the local
connection for the alarum-d-Tr csov B B into line II-According to the
answering or announcing signal the station called presses the keys Tr and Tr² and
sends currents whose direction, course and effect agree with those sent by the
calling station.
4 Speaking position.
The adjusting and contact plates as before in 63.- The corresponding stations
have the telephones receivers and lay thereby the automatic connector against the
contacts Ta Fig: 9 the contact piece 2 is also raised by this motion which
brings the contact springs p q in metallic connection and thus closes the course of
the current, battery and inducting microphone coil marked yellow.
The speaking currents travel in the calling Station from T T or M over L'H'
U. O b. or b Le Rp¹i. Le Ba into line I and from TT or M over L'ov BB
into line II and in the receiving station from line Iover a B e. L' Rp¹ e¹ L'b
or b¹ U. HLT. T. or M Lov Bẞ into Line 2.
.8. Return to the normal position.
When the correspondence is finished the calling station presses the adjusting
key T-in Fig: 8 with simultaneous turning of the inductor axis, so often till the
adjusting plate shows o again and the currents from this motion bring the contact
plates of all the other Stations back to the normal position-L on b-lift by means
of the tenon f¹ the click bolts f and release the adjusting plates which had been
closed till then.
6. Interruption of the correspondence.
Interruptions of the correspondences engaged in by giving signals or attempting
to turn the contact plates on the part of stations-not interested can never occur
ns in all stations excepting the calling ones the click bolts released by the turning
of the contact plates close the adjusting key T. and thus prevent an emission of
current over I. L. e, whereas the currents sent between C and L' for giving
signals by pressing the keys T-7 and Tr¹ find interruptions.
Secrecy of Correspondence.
The preservation of the secrecy of correspondences or despatches is perfect, as
the speaking currents in all Stations not interested only find the way from
line I over a b c L Rp e¹ L¹¹v B. ẞ to line II and owing to the interrupted
connections L' C caused by the turning of the contact plates other closings do not
exist.
The described method of connecting or silencing can be aptly termed electro
mechanical and especially in opposition to a second electro automatic method
which consists in connecting or silencing the Stations by the position of the
armature lever of the relay alone.
Material requisites and arrangements for this second method.
I For every Telegraph and Telephone Station.
a polarized relay Figs: 10 and 11 with a lever on one side of which a contact
plate is fixed insulated positive currents entering at a certain place will lay the
armature against a certain adjusting and contact scrow and keep it so long in this
position till negativo currents entering at the same place will lay the armature
over on to the other contact Screw.
II For every telegraph Station.
They can make use of any system of apparatus whatever. Three slide connectors
consisting of a transmitter and two receivers each, which are mechanically so
connected that all three can be turned round by one motion and beside the
apparati of the system in use necessary for correspondence.

page_text: III For every telephone Station,
a, a key and connecting appliance. Figs 12. 18. 14 and 15-The lever of the
connector U Fig: 12. turns in the point b, in the manner regulated by the crank K.
which moves the eccentric c Fig: 14, between and with the fork e. e. by 180° every
timo and bears at f the spring y fixed isolated which moves between the adjusting
and contact screws h and h¹ at a. a. the chase R. R turning round the screws a¹ a¹,
and finally the bearer for the screw j fixed isolated on the arm u¹ by i.
On the chase R. R. the key T is conducting and the toothed rack k is fixed
isolated.
This chase yields on the one hand to the pressure exercised by the key T. in
the vertical plane and also the opposed pressure of the spring, and by revolving
round the screws a¹ a¹ every successive motion in the horizontal plane of the con-
nector lover U or of the crank K. by turning round b The contact Sheet L revolves
round the axis m and has beyond the fulcrum two projections or arms, the one L¹
at right angles reaching upwards and the other rather downwards.
The automatic connector a to which one of the car telephones is pendent,
revolves between the adjusting and contact screws n and n¹ round the axis o, and
beyond this fulcrum is projected downwards in a¹ which arm bears at its extreme
end the isolated plate p.
The rack k, Fig: 13 in the front view, is fixed isolated on the chase R. R. turns
round the stud v, and is kept in the proper position by the pressure of the spring w,
and the striking stud v; it has three teeth of which the lowest and the highest
are in an equal vertical plane, whereas the middle tooth is projected forward by
the breadth of the prismatic ends of the contact sheet L; q, is the contact point of
rest of the key T; 7, the bearer for the contact screw v².
At the dotted position visible in Fig: 12 of the connector crank K. and of the
contact Sheet L which answers the speaking position of the connector U, the contact
sheet L lies on the lowest tooth of the rack k, and the spring g, on the contact
screw h¹. A pressure exercised on key T (calling key) in this position, pushes the
chase R. R. back and causes the contact Sheet L to fall from the lowest tooth of the
neck on to the contact screw v¹.
Out of this position the contact Sheet L can only be removed by lifting the ear
telephone pendent to the automatic connector A or by turning the connector
crank K 180° to the left.
In the first case the arm A¹ presses the end p on the arm L¹ of the contact
sheet L and lifts the latter on to the uppermost tooth of the rack k; in the second
case the screw j fixed firmly on the arin U₁ is pressed against the arm L² of the
contact plates or leaflets L, which is lifted and kept in the suspended position.
The two keys T and T and Fig 15, lying beside each other, (Answer or signal
keys), each with a resting contact a and 3, and with a working contact y¹ and y
are pressed down simultaneously by means of the button z. The keys T and T₁
are electrically connected in such a manner as to serve as commutators for the
electric current.
The object of the above described key and connector appliance combined, is:
to bring the spring g when wanted alternately in conducting connection with the
contact screws h or h¹ and the contact sheet with the rack k or with the screw j,
or with the contact-screw v', and by pressure of the keys T or T₁. to send the
electric currents in the fixed direction only.
b. An indicator: and
1. a bell for the stations working with induction currents constructed in the
shape of a common knocker, whose projecting armature strikes at evory emision of
current against a bell.
2. for the stations working with battery currents a small unpolarised relay whose
stretched armature in the local closing operates a common alarum with automatic
contact breaker.
c. A Telephone or Microphone transmitter-
with one or even two telephone receivers

page_text: d An Inductor, Fig 16 and 17.
The inductor to be employed at all stations, that have to be fitted with it, sends
at regular intervals only similarly directed currents and is so arranged, that the
direction of the turning of the inductor axis has no altering influence on the
direction of the currents.
For this purpose the ring r¹ divided into two halves and having an insulated
connection by means of the screws bb with the pinion t is mounted loose on the
axis of the inductor.
This ring has on the side facing the coil the semi-circular contact spring c
fastened by the screws d d, which grinds against the burr of the ring f, which is
fixed isolated from the coil and is in conducting connection with a wire end of the
latter.
The pinion. is turned out in the inside of the ring up to the nose shaped
piece-g, which lies-in the same-plane, as the nose h fixed on the axis of the coil.
Both beaks or noses form together the segment of a circle of 180°, in conse-
quence of which when the turning direction of the pinion t is altered, the latter
always works empty during a motion through 180° and then gears the axis of
the coil.
After one wire end of the coil is connected with the axis of the coil and the
latter with the massive and with the circuit, but the second wire end of the coil
fastened to the ring f, the currents inducted can only reach into the line so long as
the commulator spring grinding on the edge of the ring r keeps up the connection
between line, commulator, grind spring c and ring f, which is only the case during
one half of the rotation of the axis of the coil.
It is evident from this, that in rotation in the one sense only the currents (end
currents) inducted during the receding motion of the armature and in rotation
in the opposed sense only the currents (beginning currents) produced by the
approaching motion of the armature can be employed, so. that, as the direction of
the beginning currents in a rotation to the right and that of the end currents in a
rotation to the left will always be the same and other currents cannot operate, the
axis of the coil can be turned in either direction and yet send only currents in the
same sense.
1V. Methods of connection.
a. For telegraph stations: Fig 18, for Morse's system.
In the normal position visible in the drawing the current enters from circuit I
and reaches over a into the polarised relay Rp and from there over Bab (change
of slide); R (correspondence relays) c d (key contacts) and into the line 2.
When the station speaks in this position of the change of slide or cascade, the
+ current travels froin the battery over h, i j k y ba ẞ Rp a in the line II and
current from the battery over efg d and à into the line II.
the
-
As soon as two stations-the others being silenced-will or are to correspond,
they both transfer at a signal agreed upon the cascades, whereupon from one
of the two stations the first ensuing the emission of current lays in all stations not
interested in the correspondence the armature levers m of the polarised relays Rp
on to the contact-screws n and thus closes them with all apparatus of the station,
as the current then travels from line I over a Rp & m n o into line II.
-
In the speaking stations with the transferred cascades a' bhi and e¹ƒ the +
current travels from the battery over e¹ƒg dò into line II and the current from
the battery over hij ky ba¹a into line I and in the receiving stations
with transferred cascades the current travels from line I over a a¹ by Red and ô
into line II.
The closed stations cannot hear, as all apparatus of the stations excepting the
polarised relays are silenced and cannot interrupt as an alteration of the cascarle
does not disturb and emissions of current find in the contact screw k of the polarised
relay a point of interruption.
When the correspondence is concluded the cascades. are placed back and by

page_text: Having now described my invention, and the Manner in which the same is to be
performed I wish it to be understood that I claim :-
1. The manufacture and employment of electro magnetic apparatus for the
purpose of: connecting and silencing all stations in one partial chain by means of a
polarised relay without contact springs; silencing the stations not interested in
the correspondence; connecting any station whatever without disturbing the
others; and for the perfect preservation of secrecy for despatches and
correspondences by electro-mechanism.
2. The manufacture and employment of electro magnetic apparatus for the purpose
of: connecting and silencing any stations whatever connected in one partial chain
and for the perfect preservation of the secrecy of messages and correspondence; by
means of a polarised relay without contact springs.
3. The methods of connection prescribed for attaining this object.
4. The employment of-relays with two armatures of which only one operates at a
time and only in certain directions of current and only for certain moments for the
purposes already described.
5. The combination of the adjusting and contact plates with the contact sheets
and with the click bolts substantially as described.
6. The mechanical closing of the adjusting plates for a certain time and certain
purposes by means of the motion of the contact plates. The automatic manner
substantially as described and for the purpose set forth.
7 The removal or weakening of the inductive effects which arise in the multi-
plicator coils of the alarum and have such an injurious influence on the re-delivery
of the voice, by closing these apparatus out of the line, for the purpose of being
able to connect any number of telephone stations in the circuit.
8. The employment of the combination of two keys serving as commutators with
the already described key and connecting appliance for the purpose set forth.
9. The employment of the combination of the contact sheets with tooth disen-
gagement & the automatic connector for the purpose discribed.
10. The combination of an inductor axis with a loosely fixed and movable
commutator, in order to employ only currents of a certain direction or a certain
number of them, without allowing the direction in which the inductor axis rotates
to have an altering influence on the direction of the current, substantially as
described.
11. The employment of the combination of an inductor axis with a loosely fixed
and movable commutator in order to employ only currents of a certain direction
or only a certain part of them without allowing the direction in which the inductor
axis rotates to have an altering influence on the direction of the current, as
described before.
12 The employment of the invention for telegraph and telephone lines in general
and for telephone lines in particular, when the connection between the separate
stations or lines is effected by the assistance of one or more centralisation stations.
13 The employment of the invention for the arrangement of telephone cen-
tralisation stations.
In witness whereof I the said Otto Schäffler have hereunto set my hand and
Beal this 16th day of Juno A.D. 1883.