Year: 1887

page_text: Date of Application, 12th Sept., 1887
Complete Left, 12th June, 1888
Complete Accepted, 13th July, 1888
I, WALLACE FAIRWEATHER, C.E., of 62 Saint Vincent Street, in the City of
Glasgow, Fellow of the Institute of Patent Agents, do hereby declare the nature of
this invention (a communication to me from abroad by The Western Electric Company
of Chicago, Illinois, United States of America,) to be as follows:-
:-
This Invention relates to improvements in telephonic apparatus and it has for object
the provision of improved means whereby in a telephonic exchange system the
extension of an existing subscriber's line to an additional subscriber may be effected
without the use of a separate wire from the exchange and whereby with the use of a
single line wire between each subscriber and the exchange ringing off or other signals
may be communicated by any subscriber to the exchange operator without calling the
other subscriber with whose instrument connection is established, or one subscriber
may signal to another, after connection has been established through the exchange,
without at the same time calling the exchange operator.
For such purposes I employ an improved indicator which consists of a solenoid
having within its coils a permanent magnet in the form of a small bar suspended or
pivoted and balanced like a beam on a bracket piece so that it may vibrate or be tilted
on the passage through the coils of the solenoid of a continuous electric current,
whilst on the passage of alternating currents the tendency of the magnet to vibrate in
one direction is counterbalanced by a tendency to vibration in the opposite direction
and practically no movement results. Immediately over or alongside the vibrating
magnet is fitted the arm or stem of the pivotted catch which in the usual way engages
the shutter or drop of the indicator, and on said stem are fitted two prongs or pins
extending to points one just over the one end of the vibrating magnet and the other
over the opposite end so that the tilting of the magnet in either direction will have the
effect of raising the stem piece of the catch and releasing the shutter of the
indicator.
In the application of this device for the extension of a subscriber's line to a second
subscriber the solenoid indicator is connected in the first subscriber's office the solenoid
coils forming part of the line to the second subscriber's instrument, and the first

page_text: subscriber's bell may be in a local circuit closed by the shutter of the solenoid
indicator falling, when released, upon a terminal of said circuit placed on the
indicator; or the first subscriber's telephone may be joined direct to the indicator so
that the falling of the shutter on the terminal will put his instrument in electrical
connection with the line. In calling the second subscriber the exchange operator
transmits through the line an alternating current from a magneto which rings that
subscriber whilst having no action on the first subscriber's instrument, and when
calling the first subscriber the operator transmits a continuous current and thereby
acts on the magnet of the indicator and causes the shutter to drop so that by contact
of the shutter with the terminal of the first subscriber's instrument direct communica-
tion is established with that subscriber, or the local bell circuit is closed to call the
attention of the subscriber. A suitably commutated magueto is provided in the
exchange and in the first subscriber's instrument for transmitting at will either an
alternating or a continuous current, so that the first subscriber and the exchange
operator may use a continuous current in calling each other so as not to call the
second subscriber, whilst the second subscriber and exchange operator in calling each
other may use an alternating current to avoid calling the first subscriber.
To obviate replacing the existing magnetos in the exchange and subscribers'
instruments by new commutated instruments I fit a commutator on a spindle geared
from the driving wheel of the ordinary magneto and carried by a bracket fixed on the
casing of the instrument, and the collectors of the currents are connected to the
terminals of a switch which is used to direct either current into the circuit.
The arrangement above described is equally applicable to cases in which subscribers
have more than one instrument and wish to have communication directly from one
instrument with the exchange without calling an intermediate instrument.
In applying the device to permit subscribers, when placed in communication, to
call each other or the exchange, without using a separate wire for ringing off as is
usual, the solenoid indicator is switched into the subscriber's circuit by the exchange
operator in establishing communication between any two subscribers and the sub-
scribers, whose instruments are provided with commutated magnetos or other means
for transmitting at pleasure either an alternating or a continuous current, may call
each other by sending an alternating current which has no effect on the magnet of the
indicator or may call the exchange operator by sending a continuous current to act
on the magnet and bring down the shutter of the indicator upon the terminal to
automatically close the circuit of the operator's telephone.
Dated this Tenth day of September 1887
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow,
Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Telephonic Apparatus.
I, WALLACE FAIRWEATHER C.E. of 62 Saint Vincent Street, in the City of
Glasgow, Fellow of the Institute of Patent Agents do hereby declare the nature
of this invention and in what manner the same is to he performed, as communicated
to me to be particularly described and ascertained in and by the following
statement:-
This Invention relates to improvements in telephonic apparatus and it has for object
the provision of improved means whereby in a telephonic exchango system the
extension of an existing subscriber's line to an additional subscriber may be effected
without the use of a separate wire from the exchange and whereby with the use of a
single line wire between each subscriber and the exchange ringing off or other signals
may be communicated by any subscriber to the exchange operator without calling the
other subscriber with whose instrument connection is established or one subscriber may
signal to another, after connection has been established through the exchange, without
at the same time calling the exchange operator.
For such purposes I employ an improved indicator which consists as represented in
sectional elevation and plan at figures 1 and 2 and in perspective at figure 3 of the
accompanying drawings of a solenoid A having within its coils a permanent magnet
in the form of a small bar B suspended or pivoted and balanced like a beam on a
bracket piece C so that it may vibrate or be tilted on the passage through the coils of
the solenoid A of a continuous electric current, whilst on the passage through the
solenoid coils of alternating currents the tendency of the magnet B to vibrate in one
direction is counterbalanced by a tendency to vibration in the opposite direction and
practically no movement results. Immediately over or alongside the vibrating magnet
is fitted the arm or stem E of the pivotted catch which in the usual way engages the
shutter or drop 1) of the indicator and on said stem are fitted two prongs or
pins e, el, extending to points one e just over the one end of the vibrating magnet B and
the other e over the opposite end so that the tilting of the magnet in either direction
will have the effect of raising the stem piece E of the catch and releasing the shutter D
of the indicator.
In the application of this device for the extension of a subscriber's line to a second
subscriber the solenoid indicator is connected in the first subscribers office the solenoid
coils forming part of the line to the second subscriber's instrument and the first
subscriber's bell may be in a local circuit closed by the shutter of the solenoid indicator
falling when released upon a terminal of said circuit placed on the indicator; or the
first subscriber's telephone may be joined direct to the indicator so that the falling of

page_text: the shutter on the terminal will put his intrument in electrical connection with the
line. In calling the second subscriber the exchange operator transmits through
the line an alternating current from a magneto which rings that subscriber whilst
having no action on the first subscribers instrument, and when calling the first sub-
scriber the operator transmits a continuous current and thereby acts on the magnet of
the indicator and causes the shutter to drop so that the local bell circuit is closed to
call the attention of the subscriber, or by contact of the shutter with the terminal
of the first subscriber's instrument direct communication is established with that
subscriber. A suitably commutated magneto is provided in the exchange and in the
first subscriber's instrument for transmitting at will either an alternating or a continuous
current so that the first subscribor and the exchange operator may use a continuous
current in calling each other so as not to call the second subscriber whilst the second
subscriber and exchange operator in calling each other may use an alternating current
to avoid calling the first subscriber.
To obviate replacing the existing magnetos in the exchange and subscriber's
instruments by new commutated instruments I may fit a commutator on a spindlo
geared from the driving wheel of the ordinary magneto and carried by a bracket fixed
on the casing of the instrument and the collectors of the currents are in such case
connected to the terminals of a switch which is used to direct either current into the
circuit.
As indicated at figure 4 the line L from the exchange X is directly connected to
the solenoid coils of the indicator whose shutter D in falling on the sending of a
continuous current makes contact with a terminal spring d and joins up the circuit of
the local bell F in the first subscriber's office at S₁ whilst the line passing through the
indicator at D is connected to the second subscriber's instrument at S through
a switch G normally closing the line circuit to said instrument which latter is not
however affected by the sending of the continuous current. The first subscriber in
calling either the exchange or the second subscriber presses over the switch G and
uses a continuous current if he wishes the exchange and an alternating current if he
wishes the second subscriber. When the subscriber at S wishes the exchange he
sends an alternating current which has no effect on the indicator D in connection
with the subscriber at S', and if he wishes the subscriber at S¹ he may either obtain
connection through the exchange in the ordinary way or he may call the subscriber
direct by sending a continuous current which will operate on the indicator at D and
call the subscriber's attention by ringing his local bell F. In this arrangement it is
possible for each subscriber to overhear the other when engaged with the exchange.
This is overcome by employing the arrangement shown in figure 5 in which the line L
from the exchange X is connected at a terminal 1 to an extension switch G₁ of well
known kind in the first subscriber's office and the line from the second subscriber's
instrument is brought to a terminal 2, on the same switch. The telephone at S¹ is
connected to the switch at the terminal 3 and an earth wire having in circuit a
magneto bell H is connected to a terminal 4 on the switch whilst the improved sole-
noid indicator I) is placed in circuit by connection to terminals 5 and 6 on the switch.
The exchange in ringing up the subscriber at S¹ uses a continuous current thereby
drops the shutter D causing the local bell F to ring in which case the subscriber at S¹
turns the switch to the left placing himself in communication with the exchange and
at the same time cutting off the subscriber S from direct communication with the
exchange but putting his line to earth through the magneto bell H so that the
subscriber at S* may if necessary make known to the subscriber at S¹, his desire to be
connected to the exchange. The subscriber at S' after finishing conversation replaces
the switch to the central position. If the exchange operator wishes to call the sub-
scriber at S² he sends an alternating current which does not operate on the solenoid
indicator at S¹ but calls the subscriber at S2. If the subscriber at S¹ wishes to com-
municate with the subscriber at S' he presses over the switch G' to the right thereby
directly connecting his instrument to the instrument at S2 and at the same time putting
the line from the exchange to earth through the magneto bell H which permits the
exchange to call. When the switch is replaced should the subscriber at S wish to

page_text: communicate with the subscriber at S¹ he sends a continuous current which operates
on the indicator at D causing the local bell F to ring.
The arrangements above described are equally applicable to cases in which
subscribers have more than one instrument and wish to have communication directly
from one instrument with the exchange without calling an intermediate instrument.
In applying the device to permit subscribers when placed in communication to call
each other or the exchange without using a separate wire for ringing off as is usua!,
the solenoid indicator is switched into the subscribers circuit by the exchange operator
in establishing communication between any two subscribers and the subscribers whose
instruments are provided with commutated magnetos or other means for transmitting
at pleasure either an alternating or a continuous current may call each other by
sending an alternating current which has no effect on the magnet of the indicator or
may call the exchange operator by sending a continuous current to act on the magnet
and bring down the shutter of the indicator upon the terminal to automatically close
the circuit of the operator's telephone.
Figure 3 represents the solenoid indicator as thus applied, connected to the operators
telephone in the exchange.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. A telephonic indicator constructed to operate substantially as hereinbefore
described.
2. In a telephonic exchange system the arrangement of devices hereinbefore
described and whereby by the interposition of a ring off indicator two subscribers on
the same line may each communicate with the exchange without calling each
other.
3. In a telephonic exchange system the improved means hereinbefore described
whereby by the use of a single wire between each subscriber's station and the exchange
station ringing off or other signals may be communicated to either station without
calling the other.
DLL: Wth day of Tuna 1000