Improvements in Telephone Systems.
Year: 1895

page_text: Date of Application, 13th June, 1895
Complete Specification Left, 13th Mar., 1896-Accepted, 18th Apr., 1898
Improvements in Telephone Systems.
I, JOHN EDWARD KINGSBURY, of 79 Coleman Street, in the City of London,
Manager, (a communication to me from abroad by The Western Electric Company,
of Chicago, Illinois, United States of America,) do hereby declare the nature of
this invention to be as follows:-
According to this invention a small electric incandescent lamp always in
connection with the circuit line wires is employed as the call signal or indicator
at the telephone exchange-it may either be so placed as to be traversed by the
telephonic currents or when the liue of one subscriber is coupled up to the line
of another subscriber the circuit may be complete without passing through the
filaments of the lamps.
In this latter arrangement means are provided for always maintaining the signal
lamps at the exchange nearly but not quite in an incandescent state so that a
slight addition of current may raise it to incandescence.
An example of the first of these arrangements is shewn at Figure 1 and of
the second arrangement at Figure 2.
A small incandescent lamp of the ordinary type may have a resistance which
will be practically inappreciable in a telephone circuit and if its incandescing
conductor he of the loop or horse shoe form it is devoid of impedance. Hence
the lamp may be included directly in the path of the telephonic current without
diminishing or otherwise modifying the character of the current or the efficiency
of transmission.
In Figure 1 two substations A and A' are represented, each equipped with a
telephone receiver b and transmitter ', and with a telephone switch 62 adapted to
close a local battery circuit through the transmitter when the telephone is removed.
from the switch hook, and also to complete the line circuit through the telephone
receiver. This apparatus of station A is connected by line wires 1 and 2 with a
springjack or terminal socket c in a telephone switchboard at a central station D.
A signal lampe is included in conductor 1 before the latter conductor reaches the
springjack; the conductor is united with conductor 2, after being connected with
the springjack, through an impedance coilf and a battery g. The line circuit is
thus permanently closed at the central station through the signal, the impedance
coil and the battery.
The telephone line 3, 4 from the station A' terminates in a like springjack c¹ in
the switchboard, and likewise includes a lamp e¹, an impedance coil f' and a
battery g¹.
.
The usual pairs of connecting plugs adapted to fit the springjacks are provided
for looping different telephone lines together. The plugs and A' each comprise a
tip which is constructed to register with the line spring i of the springjack, and a
sleeve which is arranged to make contact with ring . The tips of the two plugs
are united by a flexible conductor 5, and the sleeves by another conductor 6.
Condensers and are included in the conductors 5 and 6 respectively..
The plug circuit 5, 6 may be provided with the usual operator's telephone and
mechanism for connecting the telephone or a source of signalling current with any
telephone line; these, being well known, are not shown in the drawing.
The line circuit 1, 2, is normally open at the substation.
When the subscriber

page_text: at station A desires to communicate with another subscriber, as for example at
station A¹, he removes his telephone from its switch hook, which rises and
completes the line circuit through the telephone receiver. The battery g is of
such strength as to create in the circuit thus completed current sufficient to
illuminate the signal lamp e. The lighting of this lamp attracts the attention
of the operator, who inserts the connecting plug h in the springjack c of the line,
and learns the order from the subscriber in the usual way. The operator then
establishes connection with line to station A¹ by inserting plug into springjack c¹
of the line and signals the subscriber in the usual way.
When the latter,
responding, removes his telephone from its switch hook, his lamp signal e¹ also
becomes lighted. If desired, however, any suitable means may be used for causing
the insertion of the connecting plug in the springjack to prevent the illumination
of the lamp.
-
Both signal lamps remain lighted so long as the circuits at the substations are
uninterrupted. It will be observed that the path of telephonic or voice currents
between the substations is through line conductor 1, traversing the lamp signal e,
thence through conductor 5 of the plug circuit, through line wire 3 to station A',
and thence returning through wire 4, conductor 6, and wire 2. The transmission
of current in this circuit is not appreciably affected by the presence of the lamps
in the circuit, while at the same time these constitute very effective signals.
When either subscriber replaces his telephone upon the switch hook, the
corresponding line circuit is again interrupted at the substation and the signal
in that line at the central station is extinguished. The obscuring of both signals
is interpreted by the attendant as indicating that the connection is no longer
required, and the connecting plugs are removed from the springjacks.
In the arrangement shown at Figure 2 the lamps are not traversed by the
telephonic currents and means are provided for maintaining the lamps nearly but
not quite in an incandescent state at the exchange so that the addition of the
signalling current which passes over the line circuit when call is made and which
frequently is of low electro motive force (the resistance of the line circuit being
often considerable) is sufficient to cause an illumination. Ready means of adjust-
ment are also provided for ensuring that whatever may be the resistance of the
particular line upon which any lamp may be placed the current passed through
the lamp to cause it to produce an illumination shall always be the same.
In Figure 2 the substations A and A' are represented as being equipped each
with a telephone receiver a and a transmitter a¹, and with a telephone switch a
which operates to close the local circuit of the transmitter and to close the line
circuit through the telephone, when the latter is removed from the switch hook.
The apparatus of station A is connected by line wires 1 and 2 with the contact
pieces 6 and 6 of a springjack c located in a telephone switchboard. The line
conductor 1 is extended through an impedance coil d and a lamp signal e to one
pole of a battery or other source f of current; the line conductor 2 is connected
through an impedance coil with the other pole of the same battery. The signal
lampe may be located near the springjack c so as to be associated with the
springjack. In shunt of the lamp and of a portion of the signalling battery,
a conductor 3 is connected, its terminals being connected with conductor 1 inter-
mediate of the impedance coil and the lamp signal, and with the battery or other
source of current at such a point as to receive a suitable electromotive force. The
conductor 3 includes a resistance coil 9 having a resistance which may be
approximately equal to or more or less than that of the lamp.
The apparatus of sub-station A¹ is connected by other line conductors 4 and
with a springjack c¹ and a line lamp e¹ in the same switchboard. The lin
conductors are extended to the poles of the common signalling battery f. A
similar local or shunt circuit is arranged for the signal lamp to maintain it more
or less near the point of illumination.
The switchboard is equipped with a pair of double connecting plugs h and h
whose like contact pieces are united by two conductors 6 and 7 respectively. I

page_text: each of these conductors of the plug circuit a condenser i may be included for the
purpose of maintaining the independence of the line-signals of two connected
lines that is, of preventing the closing of the line circuit at one substation from
operating the signal lamp of the other line. The plug circuit 6, 7, may also be
provided with the usual calling key and source of calling current for operating a
subscriber's bell, and with a listening key for connecting an operator's telephone
set with the plug circuit, to enable her to communicate with the subscribers. This
apparatus is well known, being in general use, and need not be described or
illustrated.
•
In the normal condition of the apparatus, the plugs are withdrawn from the
springjacks; the telephones at the substations rest on the switch hooks a², whereby
the line circuits are interrupted at the contact points of the switch. The portion
of the signalling battery included in the local circuit through each signal lamp
maintains in each lamp a current which does not illuminate the lamp.
Assume that subscriber at station A wishes to communicate with subscriber at
station A. The first mentioned subscriber, by removing his telephone from its
switch hook, closes together the line conductors 1 and 2 and thus completes the
circuit of battery f, the path of the current at the substation being through the
induction coil of the telephone transmitter a', the telephone a and the switch a².
A portiou of the current thus created by the battery flows through the signal
lamp e and this current being added to that already existing in the lamp circuit
the lamp will be fully illuminated.
Observing the illumination of the lamp e, the operator answers the call and
receives the subscriber's order in the usual way, and finally completes the desired
connection between the stations A and A' by inserting the plugs h and h¹ into the
springjacks c and c¹ respectively. When the subscriber at station A¹ has removed
his telephone in order to communicate with his correspondent, the signal lamp e¹ in
that line also is illuminated. The lamps remain illuminated until, the conversation
being terminated, the telephones are replaced on their switch books.
extinguishing of both signal lamps is interpreted by the attendant at the switch-
board as a signal that the lines may be disconnected.
The
If.the resistance of the line circuit 4, 5, should be different from that of the
circuit 1, 2, the resistance of the coil gi should be adjusted so as to give such a
current in the local circuit through the lamp e' that the latter will be illuminated
by the additional current in the live circuit 4, 5, to the same degree that the signal
lamp e is illuminated when its line is closed.
Obviously the same adjustment of current strength might be attained by
adjusting the electromotive force in the local circuit, the number of cells f¹
included within the local circuit being suitably varied.
Dated thin 10th day of 1905
J. E. KINGSBURY.
Improvements in Telephone Systems.
I, JOHN EDWARD KINGSBURY, of 79 Coleman Street, in the City of London,
Manager, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by The Western Electric Company, of Chicago,
Illinois, United States of America) and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
According to this invention a small electric incandescent lamp always in
connection with the circuit line wires is employed as the call signal or indicator
at the telephone exchange it may either be so placed as to be traversed by the
telephonic currents or when the line of one subscriber is coupled up to the line of

page_text: another subscriber the circuit may be complete without passing through the
filaments of the lamps.
In this latter arrangement means are provided for always maintaining the signal
lamps at the exchange nearly but not quite in an incandescent state so that a slight
addition of current may raise it to incandescence.
An example of the first of these arrangements is shewn at Figure 1 and of the
second arrangement at Figure 2.
A small incandescent lamp of the ordinary type may have a resistance which
will be practically inappreciable in a telephone circuit and if its incandescing
conductor be of the loop or horse shoe form it is devoid of impedance. Hence
the lamp may be included directly in the path of telephonic current without.
diminishing or otherwise modifying the character of the current or the efficiency of
transmission.
The drawings referred to are those left with the Provisional Specification.
In Figure 1 two substations A and A¹ are represented each equipped with a
telephone receiver b and transmitter b', and with a telephone switch 2 adapted to
close a local battery circuit through the transmitter when the telephone is removed
from the switch hook, and also to complete the line circuit through the telephone
receiver. This apparatus of station A is connected by line wires 1 and 2 with a
spring-jack or terminal socket c in a telephone switchboard at a central station D.
A signal lamp e is included in conductor 1 before the latter conductor reaches the
spring-jack, the conductor is united with conductor 2, after being connected with
the spring-jack, through an impedance coil fand a battery g. The line circuit is
thus permanently closed at the central station through the signal, the impedance
coil and the battery.
The telephone line 3, 4 from the station A¹ terminates in a like spring-jack c¹ in
the switchboard, and likewise includes a lamp e¹, and impedance coil f' and a
battery g¹.
The usual pairs of connecting plugs adapted to fit the spring-jacks are provided
for looping different telephone lines together. The plugs h and h' each comprise
a tip which is constructed to register with the line spring of the spring jack, and
a sleeve which is arranged to make contact with ring . The tips of the two
plugs are united by a flexible conductor 5, and the sleeves by another conductor 6.
Condensers & and k' are included in the conductors 5 and 6 respectively.
The plug circuit 5, 6 may be provided with the usual operator's telephone and
mechanism for connecting the telephone or a source of signalling current with any
telephone line; these, being well-known, are not shown in the drawing.
The line circuit 1, 2, is normally open at the substation. When the subscriber
at station A desires to communicate with another subscriber, as for example at
station A¹, he removes his telephone from its switch hook, which rises and
completes the line circuit through the telephone receiver. The battery g is of
such strength as to create in the circuit thus completed current sufficient to
illuminate the signal lamp e. The lighting of this lamp attracts the attention of
the operator, who inserts the connecting plug in the spring jack c of the line,
and learns the order from the subscriber in the usual way. The operator then
establishes connection with line to station A¹ by inserting plug h¹ into spring-
jack c of the line and signals the subscriber in the usual way. When the latter,
responding, removes his telephone from its switch hook, his lamp signal e also
becomes lighted. If desired, however, any suitable means may be used for causing
the insertion of the connecting plug in the spring-jack to prevent the illumination
of the lamp.
Both signal lamps remain lighted so long as the circuits at the substations are
uninterrupted. It will be observed that the path of telephonic or voice currents
between the substations is through line conductor 1, traversing the lamp signal e,
thence through conductor 5 of the plug circuit, through line wire 3 to station A¹,
and thence returning through wire 4, conductor 6, and wire 2. The transmission
of current in this circuit is not appreciably affected by the presence of the

page_text: lamps in the circuit, while at the same time these constitute very effective
signals.
When either subscriber replaces his telephone upon the switch hook, the
corresponding line circuit is again interrupted at the substation and the signal.
in that line at the central station is extinguished. The obscuring of both signals
is interpreted by the attendant as indicating that the connection is no longer-
required, and the connecting plugs are removed from the spring-jacks.
In the arrangement shown at Figure 2 the lamps are not traversed by the
telephonic currents and means are provided for maintaining the lamps nearly
but not quite in an incandescent state at the exchange so that the addition of the
signalling current which passes over the line circuit when call is made and which,
frequently is of low electro motive force (the resistance of the line circuit being
often considerable) is sufficient to cause an illumination. Ready means of adjust-
ment are also provided for ensuring that whatever may be the resistance of the-
particular line upon which any lamp may be placed the current passed through.
the lamp to cause it to produce an illumination shall always be the same.
In Figure 2 the substations A and A' are represented as being equipped each
with a telephone receiver a and a transmitter a', and with a telephone switch a
which operates to close the local circuit of the transmitter and to close the line-
circuit through the telephone, when the latter is removed from the switch hook..
The apparatus of station A is connected by line wires 1 and 2 with the contact
pieces b and b¹ of a spring-jack c located in a telephone switchboard. The line-
conductor 1 is extended through an impedance coil d and a lamp signal e to one-
pole of a battery or other source of current, the line conductor 2 is connected
through an impedance coil with the other pole of the same battery. The signal
lampe may be located near the spring-jack c so as to be associated with the spring-
jack. In shunt of the lamp and of a portion of the signalling battery, a
conductor 3 is connected, its terminals being connected with conductor 1 inter--
mediate of the impedance coil and the lamp signal, and with the battery or other
source of current at such a point as to receive a suitable electro motive force..
The conductor 3 includes a resistance coil 9 having a resistance which may be
approximately equal to or more or less than that of the lamp.
The apparatus of substation A' is connected by other line conductors 4 and 5..
with a spring-jack c¹ and a line lamp e¹ in the same switch board. The line con-
ductors are extended to the poles of the common signalling battery f. A similar
local or shunt circuit is arranged for the signal lamp to maintain it more or less.
near the point of illumination.
The switchboard is equipped with a pair of double connecting plugs hand h¹,.
whose like contact pieces are united by two conductors 6 and 7 respectively. In.
each of these conductors of the plug circuit a condenser i may be included for the
purpose of maintaining the independence of the line signals of two connected'
lines that is, of preventing the closing of the line circuit at one substation from
operating the signal lamp of the other line. The plug circuit 6, 7, may also be
provided with the usual calling key, and source of calling current for operating a.
subscriber's bell, and with a listening key for connecting an operator's telephone
set with the plug circuit, to enable her to communicate with the subscribers.
This apparatus is well known, being in general use, and need not be described or-
illustrated.
The-
In the normal condition of the apparatus, the plugs are withdrawn from the-
spring-jacks; the telephones at the substations rest on the switch hooks a' whereby
the line circuits are interrupted at the contact points of the switch.
portion of the signalling battery included in the local circuit through each
signal lamp maintains in each lamp a current which does not illuminate the
lamp.
Assume that subscriber at station A wishes to communicate with subscriber at
station A¹. The first mentioned subscriber, by removing his telephone from its
switch hook, closes together the line conductors 1 and 2 and thus completes the

page_text: circuit of battery f, the path of the current at the substation being through the
induction coil of the telephone trapsmitter a', the telephone a and the switch a².
A portion of the current thus created by the battery flows through the signal
lampe and this current being added to that already existing in the lamp circuit the
lamp will be fully illuminated.
Observing the illumination of the lampe the operator answers the call and
receives the subscriber's orders in the usual way, and finally completes the
desired connection between the stations A and A' by inserting the plugs h
and into the springjacks and respectively. When the subscriber at
station A has removed his telephone in order to communicate with his corre-
spondent, the signal lamp el in that line also is illuminated. The lamps remain
illuminated until, the conversation being terminated, the telephones are replaced
on their switch hooks. The extinguishing of both signal lamps is interpreted by
the attendant at the switchboard as a signal that the lines may be disconnected.
If the resistance of the line circuit, 4, 5, should be different from that of the
circuit 1, 2, the resistance of the coil a' should be adjusted so as to give such a
current in the local circuit through the lamp e' that the latter will be illuminated
by the additional current in the line circuit 4, 5, to the same degree that the signal
lampe is illuminated when its line is closed.
Obviously the same adjustment of current strength might be attained by
adjusting the electro-motive force in the local circuit, the number of cells f¹
included within the local circuit being suitably varied.
Having now particularly described and ascertained the nature of my said invec-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The combination with an electric circuit, of a telephone instrument contained
therein for the production and utilization of voice currents, a non-inductive
signalling appliance, and an independent generator adapted to produce an exciting
current for the said signal, both included in the said circuit, substantially as
described.
2. The combination in an electric circuit provided with a source of signalling
current and a source of telephonic current therein and a telephone receiver, of an
incandescent electric lamp adapted to be illuminated by the signalling current,
included in the circuit, substantially as described.
3. The combination with a telephone circuit including telephonic instruments for
producing and responding to telephonic currents therein, of a source of signalling
current and means for completing the circuit thereof through the telephone
circuit, and an incandescent lamp having a low-resistance loop filament adapted to
be illuminated by the signalling current included in the circuit, substantially as
described.
4. The combination with an electric signalling circuit including a source of
current and a signalling instrument adapted to be displayed when excited by a
predetermined current, of a shunt about the signalling instrument forming, with a
portion of the signalling circuit, a closed local circuit through the signalling
instrument including a source of current, the current in the local circuit being
almost sufficient to display the signal, substantially as described.
5. The combination in a signalling circuit including a source of signalling
current and divided at one point into two parallel branches, of an electric
incandescent lamp in one branch, a resistance coil in the other branch, and a
source of current in one of the branches, the normal current through the
lamp being adjusted to be insufficient to illuminate the lamp, substantially as
described.
6. The combination with a telephone circuit, of a source of current permanently
included in the circuit, and means at the substation for closing a normal interrup-
tion of the circuit, the signalling circuit being divided at one point into two
parallel branches, an incandescent lamp included in one of said branches, a

page_text: resistance coil in the other branch, a source of current in one of the branches,
the strength of the current produced in the local circuit formed by the two
branches being so adjusted with relation to the signalling current in the entire
signalling circuit that when both circuits are closed the current through the lamp
is sufficient to illuminate it, substantially as described.
7. The combination with several telephone lines having different resistances,
each including a source of electric current and normally open at a substation, and
each divided at one point into two parallel branches, of a signal lamp in one of each
pair of parallel branches and a resistance coil in the other, and a source of current
in one branch of each pair, the resistance and electromotive force in each local
circuit through a signal lamp being so adjusted to each other that the normal
currents through the different lamps and the signalling currents in the corre-
sponding lines illuminate the different lamps to the same degree, substantially as
described.
8. The combination with a telephone circuit extending between central and sub-
stations, of a partially excited signalling instrument in the circuit at the former -
station, and means actuated by the removal of the telephone from its support for
the complete excitation and operation of the said signal.
Dated this 10th day of March 1896
J. E. KINGSBURY.