Improvements in Selecting and Operating Telephones.
Year: 1896

page_text: Date of Application, 10th Mar., 1896-Accepted, 25th Apr.. 1896
COMPLETE SPECIFICATION.
[Communicated from abroad by HERBERT LAWS WEBB, of New York, U.S.A.,
Electrician.]
Improvements in Selecting and Operating Telephones.
1, THEODORE MCKENNA of 17 and 18 Basingball Street London, Solicitor and
Patent Agent, 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:-
In the drawings,
Figure 1 shows a series of six telephone stations each provided with the ordinary
telephone transmitter, receiver, and call bell, and each provided with an electrical,
transmitting and selecting instrument, and showing the position of the parts when
No. 1 has called No. 5.
Figure 2 is a top view of an impulse transmitting instrument provided with a
movable circuit changing device, the dotted lines showing the normal position of
the circuit-changer, and the full lines show the extreme position of this device.
when turned to be started.
Figure 3, a side elevation of the impulse transmitting instrument.
Figure 4 shows in full lines the circuit-changing device when it has stopped
its rotation at the end of the combination impulses, and the position of contacts at
this stage, and in dotted lines, the end of its course.
:
Figure 5 shows the normal position of the circuit-changing device and the.
position of the contacts.
Figure 6 illustrates the system as constructed for use upon a grounded circuit,
and shows the instruments in their normal positions.
Figure 7 shows the normal position of the transmitter sector, as used with the
grounded circuit.
Figure 8 is a diagram showing a number of stations legged upon a grounded
circuit.
Figure 9 illustrates the system, showing a line of six stations wherein the
communicating telephones are brought into circuit by the action of the selecting
instrument, and stations 1 and 5 show the normal position of the instruments.
whilst the others are shown in diagram.
Figure 10 shows normal position of sector D on transmitting instrument as used:
with the devices illustrated in Figure 9.
Figure 11 illustrates the system when used on single line with condeuser inter-
posed in the circuit to equalize the resistance of selector magnets, and shows the .
parts in normal position."
Figure 12 shows normal position of sector D on transmitting instrument when
the devices are used on single line as shown in Figure 11.
Figure 13 illustrates a metallic circuit upon which the instruments are arranged:
in multiple arc.
Figures 14 and 15 represent wheels having upon them a selected combination,
and answer to such a combination as may be transmitted by No. 1 station which
is responded to by the selector of No. 5 station.
The selecting instrument and transinitting instrument are shown as of a class, as,

page_text: any of the known selecting instruments will answer the purpose, and any trans-
mitting instrument adapted to operate the selectors will perform the services
required of it in this system.
The devices may be operated upon a metallic or grounded circuit.
In the drawings T-L represents the telephone line, and S-L the selector
line. Viewing Figure 1 it will be seen that at each of the stations there are placed
the ordinary telephonic devices consisting of the transmitter, receiver, call-bell, and
automatic telephone switch; each of the telephones is furnished with the usual
local battery marked L-B. The selecting instruments and their corresponding
transmitting instruments are placed on the selector line or dotted line marked S-L.
The selecting instruments therefore are operated by the transmitting instruments
and the first effect of this operation is to close the signal circuit of the bell
battery B-B.
The normal position of the telephones and their appliances is shown in the
stations 2, 3, 4, and 6 of Figure 1. The selector line is furnished with a
generator S. B. In the drawings A is a selecting instrument of any of the known
forms and as herein represented the form selected is of the class which operates a
wheel a provided with teeth or notches on its periphery and operated by an
armature lever a² of an electro magnet as a³ by means of impulses transmitted
through the coils of said magnet from an impulse transmitting instrument, adapted
to send a fixed combination or predetermined number or arrangement of impulses
corresponding with the requirements of each of the selecting instruments at the
stations on the line; it is understood that a selecting instrument, and a transmitting
instrument are placed at each of the stations, and may be operated by any member
within the circuit. The transmitting instrument on the selector line is marked B
in the drawings; on the end of an upright shaft B1 (see Figures 2 and 3) is placed
a handle b¹ intended to be turned by the hand in one direction and to be revolved
by a spring in the opposite direction, one revolution, and is stopped at the end of
the revolution by a notch in a wheel (propelled by the shaft in turning) and a
detent on a make-and-break finger which drops into the notch, the notch is
marked, and the finger 6, and the wheel . The position of this wheel with the
detent in the notch marks the end of the revolution of the wheel as well as the
stopping and starting point of the device.
In Figure 2 this position is shown; the shaft has been turned by the handle bl
and the transmitting instrument is ready to begin its reverse movement and send
out its arrangement of impulses to some one of the receiving instruments on the
line. It will be observed in viewing Figure 2 that in the form of transmitting
instrument chosen for illustration the wheel & is furnished with other notches and
raised surfaces beyond that which marks its starting point, looking to the right of
the detent around the edge of the wheel; and as the wheel revolves the detent
slides upon the raised surfaces and drops into the notches, making an irregular
series of makes and breaks at the contact 66, and these makes and breaks form the
combination or predetermined arrangement of impulses which go out to a chosen
selecting instrument, and as each selector on the line has a predetermined arrange-
ment of its own any number of disks as may be used interchangeably on the
device, or it may be provided with a multiple transmitting instrument in which a
shaft having a number of disks may be revolved, and a plug be arranged to make
contact with a brush on a particular disk, or an expert telegraph operator may
give the impulses with an ordinary telegraph key. When a receiving instrument
has received its particular arrangement of impulses, it works out to the end, and
any additional impulse thereafter will restore it to its starting point; as there are
a number of such instruments they may be said to be well known and require no
further explanation. The gearing in the transmitting instrument is so arranged
that the handle b' may be turned in one direction leaving the wheel 6 at rest
and ready to be started as shown in Figure 2, by the reverse movement of
the shaft; such an arrangement of gearing is well known and needs no further
explanation.

page_text: Viewing Figures 2, 14, and 15, No. 15 represents the wheel on the selecting
instrument; 2 and 14 representing the wheel on the transmitting instrument. It
will be seen that when the wheel is started the following arrangement will follow:
2-space-2-space-3-space-3-space-1. This brings the wheel & on the
transmitting instrument to a point where the detent on the finger & enters the
notch b' (see Figures 2 and 14) aud the wheel on the selecting instrument (see
Figure 15) into the corresponding notch &'; the selector wheel has at this point
reached the end of its course and has performed the work, required of it and is
ready at the proper time to be returned to zero or starting point, the wheel on the
transmitting instrument is stopped at this point leaving a space to be traversed
between the notch &and the end of its revolution or starting point represented by
the notch &, which wheel when released, as will be explained, makes the necessary
break which returns the selecting instrument to zero, which is done after the
parties have ceased their conversation through the telephone.
Suitably attached to a part of the frame-work of the selecting instrument are two
contact springs c-cl; these springs are normally open and are closed by the wheel
of the selecting instrument, in responding to its predetermined arrangement of
impulses.
The wheel a of the selecting instrument as before described has its combination
arranged around its edge, and at a point on its plane there is placed a pin a* which
revolves with the wheel and strikes the spring e furcing it against its companion
spring e; this occurs when the combination impulses are completed and the detent
on the finger b of the transmitting instrument is resting in the notch b', and the
pawl on the armature lever of the selecting instrument is holding the wheel and is
in its notch 67.
Viewing Figures 2, 4 and 5, there is shown attached to the main shaft, a sector D,
which turns with the shaft; the normal position of this sector is shown in Figure 5.
The extreme position of this sector when turned by the hand is shown in Figure 2,
and when released is revolved by its spring in the direction of the arrow until it
has accomplished a complete revolution of the wheel and returns to its starting
point as shown in Figure 5 and in the dotted lines in Figure 2; a part of the rim
of this sector is provided with insulating material as shown by the heavy black
lines, and part of it with conducting material as shown by the space between the
black lines, and against the edge are placed the three contacts 1, 2, 3. These
contacts regulate the telephone circuit in accordance with the position of this
sector; when the sectors are in normal position as shown in Figure 1, in stations 2, 3
and 4, the telephone circuit is as follows: Beginning at the left, to spring e', thence
to contact No. 3 on the sector D, thence across conducting space to contact No. 2,
and thence out to line: when this sector has been revolved by its spring it is
stopped before it reaches the end of its course by suitable mechanism for that
purpose; the means shown herein for stopping it are exhibited in Figures 2 and 3;
upon a suitable part of the frame-work is placed the spring E, and may be provided
with a catch or projection e', and upon the sector is placed a pin 2 which comes in
contact with the catch and stops the revolution of the sector at a point in Figure 4;
it will be seen that contact No. 3 is now on the insulated part of the sector, and
Nos. 1 and 2-are joined by the conducting surface; the telephone circuit as above
described is then broken at No. 3 whilst the catch and pin are holding the sector,
the detent on the finger is resting in the notch &, of the wheel , and this last
impulse bas stopped the combination wheel of the selecting instrument at the end
of ita combination and is holding it there with the pawl of the armature lever in
the notch of the selector wheel, and the pin on that wheel has just closed the
springs c, this position of the two stations is represented in Nos. 1 and 5 of
Figure 1; the bell is now ringing at No. 5 station, and the circuit is from bell-
battery B-B to spring c, thence to c', thence to springs, to bell magnet, and
to battery; the party called at No. 5 station now takes his receiver off the hook,
preparatory to receiving the communication: upon an insulated frame as 9 are
erected the contact springs fffff, through which the circuits are

page_text: opened and closed by the upward and downward movement of the automatic
telephone switch a-t-s; when this switch is down it closes the bell circuit
through the springs -, and when the receiver R is taken from the hook the
switch ascends and the circuit is broken at the springs f-f¹ and the bell stops
ringing. Now beginning at station 1, the telephone circuit is-to switch a--, to
spring, to receiver, to secondary winding of induction coil, to contact No. 1 of
sector of transmitting instrument, thence to contact No. 2, and out to line; and the
primary circuit of the telephone transmitter is from battery L. B, to telephone
transmitter, thence to winding of induction coil, thence to springs and f³, and
thence to battery. In No. 5 station the telephone circuit goes to switch a--8,
thence to spring, to receiver R, to secondary winding of induction coil, to
springs cc, to contact No. 3 on transmitter sector, thence to contact No. 2 and
out to line; the parties are now ready to converse by telephone in the ordinary
way, whilst the instruments are held in their respective positions as described.
When the conversation is over the receivers are hung upon the hooks and the
catch-spring E of the transmitting instrument is depressed by pressure upon the
thumb button e; this releases the sector D, when its shaft revolves and finishes its
course, restoring the parts to the starting point, and as the detent on the finger
rises out of the notch and rides upon the adjoining space, it makes the necessary
break in the circuit which operating upon the selecting instrument restores that
instrument to starting point."
This system of selective telephone service may readily be carried out on a
grounded circuit as illustrated in Figures 6, 7, and 8, or on a metallic circuit with
the instruments connected in multiple arc (instead of in series) as illustrated in
Figure 13.
Viewing Figure 6, it will be seen that seven stations are shown, of which
stations 1 and 6 show all the appliances of the device and the others are represented
in diagram. As shown in the drawing the line T-L is connected by a short
conductor to the spring e' erected upon the base of the selecting instrument in
position to be forced against its companion spring c, by the pin a' on the wheel a¹.
In the arrangement of the device upon the grounded circuit as shown in the
drawings Figures 6 to 8, there have been made some convenient changes in the
springs located within the frame or box g, which are operated by the movement of
the automatic telephone switch a-t-s, the springs form the terminals for
the primary circuit of the telephone transmitter. It also facilitates the use of two
contacts 1 and 2 upon the sector D instead of three as illustrated in the drawings
hereinbefore described as shown in Figure 7 which illustrates the normal position
of this sector when the line is not in use. In this normal position of the operative
parts of the device the telephone circuit is open and the selector circuit shown by
the dotted lines S-L is through the coils of the selector-magnet a³, thence through
the selecting instrument and out to line, or vice versa, as the relative position of the
selector and transmitting instrument at the stations are immaterial as they are all
- connected on the line in series.
Viewing Figure 7, it will be seen that station No. 1 on the line will send out a
call to station No. 6, by turning the sector shaft of the transmitting instrument and
allowing it to be reversed by its spring. The sector D will pass through its reverse
movement, transmit the combination impulses to No. 6 station and the sector will
stop at the end of these impulses, with the contacts 1 and 2 resting upon the
conducting surface.
At No. 6 station the wheel a¹ of the selecting instrument will force spring e
against its companion spring c. This action will close the bell circuit at
No. 6 station, which runs from battery B-B to spring contact, to switch a--
to springs c and c', to bell-magnet, to battery. The parties at the two stations now
take the receivers R off the hooks on the switch a-t-s, which then rises and
closes springs f-f, and makes contact with ; the bell circuit of station 6 is
now broken at f; the telephone line at station 1 runs from spring e¹ to contact 2
on sector D, thence to contact 1, thence to switch a-t-s, to spring, to secondary

page_text: winding of induction coil, to receiver R, to ground; and the primary circuit of
telephone transmitter runs from battery to telephone transmitter, to primary
winding of induction coil to springs f, to battery; at No. 6 station the
telephone circuit entering at spring e, runs thence to spring e, thence to
switch a-t-s, contact f³, to secondary winding of induction coil, to receiver R,.
to ground; and the primary circuit of telephone transmitter is from battery L-B
to telephone transmitter, to primary winding of induction coil, to springs fi-f', to
battery; the parties at the two stations are now ready to converse, whilst the
instruments are held in their respective positions; when the conversation is over,.
the receivers are hung upon the hooks of the switches, the spring E at station 1 is
pressed, releasing the transmitting instrument to finish its revolution and make the
necessary break in the circuit which restores the selecting instrument at No. 6
to starting point and brings the devices to their normal positions as shown in
Figure 6.
Figure 13 illustrates by way of diagram the method of connecting the telephone
station in multiple arc circuit.
Figure 9 illustrates a selective telephone system whereby the automatic switch is:
dispensed with and the conversing parties put into communication with each other
by the operation of the transmitting and selecting instrument alone and held in
position until the end of the conversation when the devices are released and restored
to normal position.
Figure 9 represents a line of six stations, of which stations 1 and 5 show the-
normal positions of the instruments. The telephone line T-L is connected with
the base of spring c', and the transmitting and selecting instruments are in circuit
with the selector line S-L which runs through the coils of the magnet of the
selecting instrument, thence through the transmitting instrument, and out to line :
connected with one of the contacts, as No. 1 in the drawings, is a conductor which
terminates in a key K, designed to be pressed by the thumb button k¹, and be
stopped in its up and down movement by the two contacts 3 and 4.
From the spring e a local line L-L runs to a magneto telephone R, and thence
to ground, and from this line a branch 1-1 runs to contact No. 3; from contact
No. 4 a line runs to contact 5, thence through armature h, through the coils of an
electro-magnet H, thence to battery L-B, thence to ground.
When a call has been made from No. 1 to No. 5, No. 1 station has called No. 5
by sending out from the calling station the combination or predetermined arrange-
ment of impulses which answer to No. 5 station. No. 1 (the caller), has started
off his transmitting instrument which has finished the arrangement of impulses on
its wheel and has stopped with the contacts 1 and 2 upon the conducting space of
the sector D; the current is then from line T-L to base of spring e', thence to
contact No. 2 on sector D, thence to No. 1, thence to contact No. 3, and branch
to line L-L, through magneto telephone, to ground: at No. 5 station the selecting
instrument has closed the springs c-c and the current entering from line T-L at
spring c, runs thence to spring c, thence by line L-L through magneto telephone
to ground: the parties are then in position for conversation, and the devices are
held in this position as heretofore explained by stopping the sector D of the
transmitting instrument at station 1, which holds the selecting instrument at station 5,.
with the springs c-c closed until the end of the conversation. When the two
telephones are thus connected the caller at No. 1 presses the button k¹ which gives
an interrupted current and makes a noise in the magneto-telephone R, which is
sufficient to signal the party at No. 5 that his station is called at the end of the
conversation the sector D at the calling station is released to finish its course and.
restore both stations to normal position.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be perforined, I declare that what.
I claim is:-
1. In a selective telephone system a single line on which is placed a telephone

page_text: and a single line on which are placed an impulse transmitting instrument and a
selecting instrument at each of the stations, means operated by each of the selectors
in response to impulses from any one of the transmitting instruments over the selector
line, to thereby bring into circuit and connect the communicating telephones with
each other.
2. In a selective telephone systein a single line on which is placed a telephone,
and a single line on which are placed an impulse transmitting instrument and a
selecting instrument at each of the stations, means operated by each of the selectors
in response to impulses from any one of the transmitting instruments over the selector
line, to thereby connect the communicating telephones with each other, and means
operated by a vibratory current transmitted through the telephone line when the
communicating telephones are connected to thereby sound an audible signal at
the station called.
3. In a selective telephone system a single line on which is placed a telephone
and a single line on which are placed an impulse transmitting instrument and a
selecting instrument at each of the stations, means operated by each of the selectors
in response to impulses from any one of the transmitting instruments over the selector
line to thereby sound an audible signal and prepare the telephone lines to admit
the communicating telephones into circuit with each other, and means actuated by
the telephone switches, to thereby connect the communicating telephones with each
other and cut out the audible signal.
4. In a selective telephone system the combination with two or more telephone
circuits, of a single line on which is placed a telephone and a single line upon which
are placed an impulse transmitting instrument and a selecting instrument at each
of the stations, means operated by each of the selecting instruments in response to
impulses from the transmitter over the selector line to call up any one of the
stations, and means operated by the telephone switches to connect the communicating
telephones with each other.
5. In a selective telephone system a single line on which is placed a telephone
and a single line on which are placed an impulse transmitting instrument and a
selecting instrument at each of the stations, means operated by each of the selecting
instruments in response to impulses from the transmitter over the selector line to
call up any one of the stations, means operated by the telephone switches to
connect the communicating telephones with each other, and means for retaining
the circuit through the communicating telephones during the conversation.
6. In a selective telephone system a single line on which is placed a telephone
and a single line on which are placed an impulse transmitting instrument and a
selecting instrument at each of the stations, means operated by each of the
selecting instruments in response to impulses from the transmitter over the
selector line, to call up any one of the stations, means operated by the telephone
switches to connect the communicating telephones with each other, and means
operated by the transmitting instrument to retain the circuit through the com-
municating telephones during the conversation and to restore the instruments to
starting point when the conversation is closed.
7. In a selective telephone system the combination with two or more telephone
stations, provided with their respective telephones arranged upon a single line, of a
selector line having in its circuit an impulse transmitting instrument and a selecting
instrument at each of the telephone stations, and means operated by each of the
selecting instruments in response to any one of the transmitting instruments to
prepare the telephone line to admit the communicating telephones into circuit with
each other.
8. In a selective telephone system the combination with two or more telephone
stations each provided with its respective telephone arranged upon a single line, of
a selector line provided with an impulse transmitting instrument and a selecting
instrument located at each station, means operated by each of the transmitting
instruments to select and operate any one of the selecting instruments on the line
and thereby signal its respective station, and devices operated by the transmitting

page_text: instrument in sending out its signaling impulses to prepare the telephone line to
establish circuit through its telephone switches.
9. In a selective telephone system the combination with two or more telephone
stations each provided with its respective telephone arranged upon a single line, of
a selector line provided with an impulse transmitting instrument and a selecting
instrument located at each station, means operated by each of the transmitting
instruments to select and operate any one of the selecting instruments on the line,
and prepare the telephone line at the selected station to establish circuit through
its telephone switch.
10. The combination with an electrical impulse transmitting instrument, a
selecting instrument in circuit therewith and adapted to he selected and actuated
by impulses therefrom, of devices for arresting the movement of the transmitting
instrument before it has completed its course and thereby arrest and hold the
selecting instrument and prevent it from returning to normal position.
11. In a selective telephone system the combination with two or more telephone
stations, each provided with its respective telephone arranged upon a single line, of
a selector line provided with an impulse transmitting instrument and a selecting
instrument located at each station, devices for arresting the movement of the
transmitting instrument before it has completed its course, and thereby adjusting
the instruments at both stations to establish the circuits through the communicating
telephones.
12. In a selective telephone system, the combination with two or more telephone
stations, of a telephone, an impulse transmitting instrument, and a selecting
ment at each station, and means operated by each of the selecting instruments in
response to its predetermined arrangement of impulses from any one of the
transmitting instruments to connect its respective telephone and no other with the
calling station.
13. In a selective telephone system the combination with two or more telephone
stations of a telephone, an impulse transmitting instrument and a selecting instru-
ment at each station, means operated by each of the selecting instruments in
response to its predetermined arrangement of impulses from any one of the trans-
mitting instruments to connect its respective telephone and no other with the calling
station, and means operated by the transmitting instrument to retain the
communicating telephones in circuit during conversation.
14. In a selective telephone system the combination with two or more telephone
stations, of a telephone, an impulsė transmitting instrument and a selecting instru-
ment at each station, means operated by each of the selecting instruments in
response to its predetermined arrangement of impulses from any one of the
transmitting instruments to connect its respective telephone with the calling station,
means operated by the transmitting instrument to retain the communicating
telephones in circuit during conversation, and means for restoring the instruments
to normal position when the conversation is closed.
Dated the 10th day of March 1896
THEO. MCKENNA.