Improvements in and relating to Switch Boards to be Used for. Telephonic or Telegraphic Purposes.
Year: 1896

page_text: Improvements in and relating to Switch Boards to be Used for.
Telephonic or Telegraphic Purposes.
We CHARLES SHORE of 125 Chorley Old Road Smithills Bolton Electrician
and CHARLES HEAT of Caldershaw Rochdale Dyer and Fulling Miller both in
the County of Lancaster, do hereby declare the nature of this invention to be as
follows:-
This invention relates to apparatus or switch boards for use in telephone exchange,
central or other stations or switch rooms or for other analogous purposes by means
of which the operation of connecting subscribers for the purposes of speech
communication may be greatly facilitated.
According to our invention communications may be affected between subscribers
with efficiency and celerity as we obviate the existence or creation of faults due to
certain defects as are now found in practice with the present construction of boards
in which flexible textile or fibrous covered plug attachments or covered wires
known as "cords" are employed in connection with the jack plugs.
The salient feature of our invention consists in dispensing entirely with the use
of or necessity of "cords" or plug and speech transmitting attachments covered
with textile coverings as now employed.
Our invention consists of a novel construction of jack and plug any number of
which may be employed in connection with a board such number being that which
may be found inost convenient for manipulation by an operator and such number
employed or distributed on a board or boards in a station or exchange and
connected in nltiple series as and in the manner as is now well known.
We will now proceed to describe in detail the construction of our new board or
apparatus.
We will first proceed to describe the switchboard that is, the board apart
from the jacks and the plugs both of which will be more particularly described in
detail hereafter.
The board or apparatus consists or is when built up composed of a series of
rectangular shaped and hollow pieces each piece has two sides or parts in proximity
to each other open at one end but closed at the opposite end which thus forms a
hollow case like piece each side at its inner part is constructed, formed, composed
or built up of sectional parts or strips of conducting and non-conducting materials
respectively which may be for example strips of metal and ebonite.
The strips of metal and ebonite are suitably bound together and so arranged as
to form the inner sides or surfaces viz. a a¹ of the said bollow case like piece of
alternately arranged strips of metal and ebonite and extending lengthwise thereof,
that is, a strip of ebonite then a strip of metal and so on throughout or across the
width of the pieces according to the number of metal strips required which is
subject to the number of subscribers to be provided for on the board, that is, each
metallic strip or section is provided to form a medium through and by means of
which when provided with the plugs two persons may communicate with
each other.
In the construction of our board a number of such apparatus may be employed

page_text: in any suitable position with relation to each other preferably one above the other
and in each of which the correspondingly situated pieces or metallic sections are
suitably wired together so that each corresponding individual section shall form
throughout the series a means or medium for communication as hereafter
described.
For convenience of description we shall employ the term "cominutator" when
referring to the case apparatus hereinbefore mentioned.
We preferably form or divide the aforesaid metallic strips into sub-sections or
parts, that is, we form the same into three or more parts or separate pieces each
suitably insulated from the other which arrangement we employ for multiple
connections or for boards connected in multiple series whereby we are enabled to
'accommodate a great number of subscribers in a emall or compact space and to
meet the requirements as to the control by an operator of a large number of jacks
which is an essential requisite of an effective board according to the present system
and thus our invention is adapted to meet such requironients.
According to a modification of the above description the "commutator" may be
constructed from a "solid rectangular shaped piece or block of ebonite" or other
non-conducting material, that is, not of hollow divided or case-like form as in the
foregoing description which according to this our modification we slot or recess
lengthwise and at suitable intervals of its width and insert, that is, in the slots or
recesses metallic pieces or strips therein thus forming alternate sections of ebonite
and metal respectively as in the form hereinbefore described and from the one side
of the said piece, that is, from the front or outer side parallel with the strips or slots
we bore or form at suitable distances apart or intervals holes or circular apertures
the said metallic strips are also provided with apertures corresponding to the
apertures in the ebonite piece so that when the strips are placed in position within
the slotted parts of the anid piece an aperture or circular opening is formed for a
suitable distanco transversely to the said piece or commutator consequently forming
a thoroughfare composed throughout its length alternately of strips of metal
and ebonite respectively which thoroughfares constitute at such parts jacks of
circular form and admit of the use of a plug of corresponding form.
We will now proceed to describe the construction of the jack proper that is
the part of the commutator board adapted to recoive or prepared for the reception
of the plug.
According to our invention the jack consists of two line pieces or springs which
are arranged or situato transversely or across aud outside and on opposite sides of
or within the "commutator" or in the case of a trunk board the two line springs
are situate on the one side of the "commutator" and outside thereof the former
description that is, a spring each side of the "commutator" refers more particularly
to a local board. The front extremities of the line or spring pieces, i.e. situate at
the front or face of the "commutator" are adapted so as to form a mouth or
entrance to the jock the opposite ends thereof are connected with the loop. The
extremities or mouth of the spring pieces extend beyond the face or front of the
"commutator."
In connection or in proximity to the line spring pieces we employ conducting or
continuation pieces provided with contact points which points when the plug
hereinafter described is not within the jack-are in engagement with the said line
ieces the function of which continuation pieces is to continue or form media or
means for transmitting or carrying the current from the loop to and forming
connections with correspondingly numbered jacks on the same board or other
boards in the exchange tho use of which connections or continuation pieces is
well known.
The arrangement of test click connections in accordance with our invention in
the construction of a trunk jack is as follows. At the lower side of the "com-
mutator" is a test click spring piece which when the plug is inserted into the mouth
of the jack the said spring is adapted to yield distend or depress so as to make
contact with a secondary spring piece in proximity thereto which normally rests

page_text: against a piece in circuit with the operators receiver so that if a current be on the
test click spring of this particular jack (as the test click spring of each jack is
when the jack is in use placed in contact with one and the same or continuous piece
or strip of metal traversing throughout the boards in the exchange and which latter
piece is in a trunk board placed in circuit with a test click battery) n eliokiag noise
will be beard nt the operator's receiver announcing the jack as engaged on some
other board but if no current be on the line then on the complete insertion of the
plug which is suitably formed to actuate the said spring piece the test spring piece
is then further deflected or depressed causing the secondary spring piece to further
depress and to remove out of contact with the operators circuit piece and placed in
engagement with the test click battery piece before named thus the test click is
then by reason of multiple connections put on the test click spring or line of a
correspondingly numbered jack or jacks situate on any other board or boards.in
the exchange.
The arrangement now and just above described constitute the test click arrange-
ment of our trunk jack the function of which on a trunk board is to receive
intimation from or to announce to an operator on any other board the engagement
of any particular subscribers jack as the number of every subscriber's jack in the
station or exchange is provided on each and every hoard anl connected in multiple
series or parallel which is in accordance with present practice. The other
accessories or the line springs for the trunk jack is as hereinbefore stated situate at
the upper part of the "commutator."
In the construction of a local jack in contradistinction to the trunk jack the said
jack is composed as follows. A line spring is sitante on the top or one side of the
"commutator" having a continuation spring. A line spring is also provided on the
bottom or opposite side of the "commutator" but without a continuation spring
the line apring in this case being connected to similar pieces before described for
the test click purposes, but the test click buttery piece is not employed as the line
spring in this case acts also as a test click spring but in the case of putting a
current on the test click line in this board this is effected at the operator's switch
through a retardation coil in the usual manuer, and by a suitable connection with
each strip of the "commutator" the test click is accomplished upon the introduction
of a plug and making contact with the strip so connected, thus, a clicking noise
will in like manner as above described be heard by the operator on his board, if
the jack corresponding to the number wanted by such operator be engaged on any
other board in the exchange.
Each metallic section or sub-section in each "com'nutator" thronghout the
whole series are suitably connected together by means of suitable wiring that is
the said sections forming the inner sides of the "cominutator" as herein first
described are each connected to the operator's switch so as to form a complete
circuit when a subscribers plug-hereinafter described is inserted in the jack or
between the space intervening hetween the said sections, that is, in the hollow form
or case like "commutator."
Each metallic section of the "commutator" baving jacks of circular form
heroin secondly deseribed is also suitably wired and put into conuection with
the operators switch and a complete circuit effected upon the introduction of a
plug adapted for this particular construction of "cominutator" and hereinafter
described.
We will now preceed to describe the construction of plug adapted to be need
with the two forms of "commutator" herein described.
We will firstly describe the plug to be used in connection with our "commutator"
of the first or hollow form.
It must be understood that in connection with each jack we assign two or a pair
of plugs for either form of jack the plugs used throughout the hoard are facsimiles
of each other but with certain slight differences which will be hereafter explained
two plugs being necessary as in present systems to effect a speech c.unmunication
between two persons on local boards, but on a board according to our invention aud

page_text: when used as a trunk board for connecting trunk and junction lines one plug only
is required to put the said lines into connection with each other.
When a pair is employed in any two jacks on the board a circuit only is effected
thereby with or through the medium of oue and the same continuous metallic
section connected throughout the series of "commutators" inter se, by suitable
wiring as before named.
The plug is provided at one end with a handle its other end i.e. the part adapted
to enter the jack is provided with metallic contact pieces and project beyond the
surface of the bollow constructed plug or case. The lengths or extent of the
contact pieces from the handle of cach plug varies in order to accommodate and
according to the distance of each metallic strip or sub-sectional strips within the
jack that is, from the front of the "commutator" or face of the board so that when
the plug is inserted within the jack contact shall be made with two of the sections
or subsectione only thus a pair of plugs is su adapted to make contact with the
same sections or sub-sections of any two jacks of the "commutator"
"commutators" composing the board consequently each pair of plugs complete a
circuit thro' which speech may be transmitted.
or
The plug constructed for use with the first herein described "oommutator" has
the metallic coutact pieces of equal lengths as the motallic sections are in this
construction two separate pieces aud are situate in juxtaposition to each other; but
in the plug to be used in the secondly described form of "commutator" i.e. the
circular jack the contact pieces are of unequal lengths that is, one contact piece is
longer than the other as in such construction of jack the "commutator" is built
up in this case by means of metallic sections or contact strips in whole or undivided
pieces and arranged in the ebonite or other block or piece in manner before
described but such strips are not placed opposite to each other in this case but
next to each other but intercepted from each other by the insulated parts before
named the two contact pieces of the plug are arranged to make contact with two
strips thus of necessity one must be longer than the other otherwise if both were
of the same length contact would be made only with one piece or whole strip
consequently short circuit would result, the plug and the mouth of this form of jack
is also adapted and arranged in suitable manner to avoid short circuit.
In connection with our invention any of the well known systems for ringing may
be employed. If a system of ringing be employed which involves the ringing of
the subscriber by the operator we employ two colored ringing keys provided so as
to correspond with the colored handles of each pair of plugs, that is, one may be
for example black the other white.
This is accomplished by connecting with a suitable ringing apparatus which may
be of any ordinary construction which ringing apparatus is suitably connected to
certain sections or subsections of the metallic strips of the "cominutator" which
ringing connections are so arranged that either one of any two subscribers shall be
rung up at a time at the discretion of the operator by the insertion in the jack of a
black or white handled plug.
The general operation of our invention is as follows:
The person operating will have under control or for disposal pairs or duplicate
plugs on the operators table the number of pairs of plugs correspond with the
number of jacks allotted to the operator but each operator's board will be provided
with the number of jacks corresponding to the uumber of subscribers in the
exchange in the case of a multiplo board and the whole of which will be situate in
any suitable or convenient position thereou as is ut. present the case, and the jacks
on each board connected together in multiple series and with the loop in the
ordinary and well known manner.
The operator on answering a subscriber's call will first pull over a switch any
switch which is not in use may be used then take up one of the pair of plugs in
proximity to the switch xo pulled over and insert it in the subscribers jack making
the call, then take up the other plug and insert it in the subscriber's jack whose
Dumber is asked for.

page_text: But on first inserting the plug in the subscribers jack whose number is asked for
the said plug being of anitable form and proportion actuates the test click spring
at the entrance to the "commutator" jack so as to cause the said spring to engage
with a secondary spring which is in circuit with the operator's receiver in the
event of the subscriber's line asked for being engaged on any other board in the
exchange the test click spring of the anid jack is through the medium of multiple
connections charged with a current as the test click spring of the correspon-ling
jack on the other board is plared in airenit with the test click battery piece, thus
a elicking noise will be heard at the operator's receiver consequently the said
subscriber's line would by such clicking noise or sounds be announced as engaged
but if the line wanted he not engaged on any other board in the Exchange the plug
on being then completely inserted within the jack the line springs are then due to
the form of the plug moved out of contact with the continuation pieces a speaking
communication is then opened or a complete circuit effectel on or through twor
the same continuous metallic sections throughout the board or boards with which
sections only two persons are capable of being put into communication through the
medium only of the pair of plugs assigned to each operator's switch as the sail or
any pair of plugs so assigned can only make contact with the same or corresponding
metallic sections throughont the "commutator" as the contact pieces of each plug
are facsimiles of each other as before fully described, and which pair of plugs
complete the apenking circuit.
Consequently the test click apparatus of this particular jack is brought into
action and operates on the test click arrangement of a correspondingly numbered
jack on any other board or boards in the Exchange.
We would have it understood that uur apparatus may be applied or used in
connection with call wire or other systems now in use.
This invention is particularly important for use in trunk exchanges as by its use
the operation of connecting subscribers or trunk and junction lines will be greatly
facilitated as one plug will only be required for such purpose as by means of the
construction of the "commutator" jack the operator's switch performs the office
of a jack and plug thus one plug and jack will according to this invention be
employed instead of two plugs and jacks as will be the case according to the
present construction of many telephonic switch boards.
The application of our invention for the above purpose that is for use in
connection with trunk and junction lines is as follows;-
Each trunk line is connected with or put in circuit with a suitably constructed
operator's switch which switch is also in circuit with the wires or connections of
each "commutator" strips or metallic sections of the switch board and which
operator's witch is also in circuit with the usual accessories such as annunciators
and receivers &c. The operation of this part of our invention is as follows:-
When a signal is sent from the trauk office, that is from the office having the
control of the trunk lines or inter-town connections for example in this centre
H. M. Post Office to the Telephone Exchange centre which centre hus the control
of the junction lines or Subscribers wires and which trunk lines are extended from
the Post Office switch room to the Exchange centre, the annunciator drops in the
Exchange switch roum the operator upon receiving instructious from the trunk
office to connect any particular trunk with a subscribers or junction line operates
the switch puts the trunk line in circuit with a pair or tw metallic sections of
the "commutator" inserts the plug in a jack being the number of the subscribers
jack asked for as the subscribers in the Exchange are distributed on the board
thus a through communication is opened between the two persons on the trunk
and junction lines and anch is accomplished by the use of one plug and the
operator's switch. It will be manifest that the operation is similar in the event
of the Exchange requesting through connection on the trunk lines, that is, from
the Telephone Exchange to the trunk office.
We have now fully stated the nature of our invention, speech may thus be
eflected without the aid or employment of cord like or flexible and fibrous or textile

page_text: -covered plug connections or attachments as now employed which parts or
connections have been found in practice to become defective and productive of
faults due to faulty connections as the covering the fibrous or other coverings
of the wire plug. connections become by use worn thus exposing or laying bare the
wires hence the abnormal contacts during manipulation of the plug in the switch
room with some other metallic or conducting surface consequently interruptions of
speech and the creation of faults as before named results which it is the sole object
and purpose of this our invention to remedy and which we claim to accomplish by
the means herein before set forth in the foregoing description.
Dated this 25th day of April 1896.
J. H. BUTTERWORTH,
Rochdale,
Fer the Applicants.
Improvements in and relating to Switch Boards to be Used for
Telephonio or Telegraphic Purposes.
We CHARLES SHORE of 7, Meal House Lane late of 125 Chorley Old Road,
Smithills Bolton Electrician and CHARLES HEAP of Caldershaw, Rochdale,
Dyer and Fulling Miller both in the County of Lancaster 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 :-
This invention relates to apparatus or switch boards for use in telephone
exchange, central or other stations or switch rooms or for other analogous purposes
by means of which the operation of connecting subscribers for the purpose of
speech communication may be greatly facilitated. According to our invention
communications may be effected between subscribers with efficiency and celerity,
as we obviate the existence or creation of faults due to certain defects as are now
found in practice with the present construction of boards in which flexible textile
or fibrous covered plug attachments or covered wires known as "cords" are
employed in connection with the jack plugs. The salient feature of our invention
consists in dispensing entirely with the use of or necessity for "cords" or plug and
speech transmitting attachments covered with textile coverings as now employed.
Our invention consists of a novel construction of jack and plug any number of
which may be employed in connection with a board such number being that which
may be found most convenient for manipulation by an operator, and such number
employed or distributed on a board or boards in a station or exchange and may be
connected in multiple series as and in the manner as is now well known.
We will now proceed to describe in detail the construction of our new board or
apparatus.
We will first proceed to describe the switch-board that is, the board apart from
the jacks and the plugs both of which will be more particularly described in detail
hereafter.
The board or apparatus consists or is when built up composed of a series of
rectangular shaped pieces each piece has a side or part in proximity to each other
which thus form a series of hollow cases, cach side, at its inner part is provided
with strips of metal lengthwise of the ebonite piecos.
The strips of metal are so arranged as to form the inner sides or surfaces of the
said hollow case like picces of alternately arranged strips of metal and ebonite
and extending lengthwise thereof, that is, a strip of ebonite then a strip of metal
and so on throughout or across the width of the ebonite pieces according to the
number of metal strips required, which is subject to the number of subscribers to
be provided for on the board, that is, each pair of metallic strips or sections are

page_text: provided to form a medium through and by means of which when provided with
the plugs two persons may communicate with each other.
In the construction of our board a number of such apparatus may be employel
in any suitable position with relation to each other, preferably one above the
other, and in each of which the correspondingly situated pieces or metallic
Bections are suitably wired together so that each corresponding individual section
sball form throughout the series a means or one continuous medium for
communication as hereafter described.
For convenience of description we shall employ the term "commutator" when
referring to the case apparatus hereinbef. re mentioned.
We may form or divide the aforesaid metallic strips into sub-sections or parts,
that is, we may form the same into three or more parts or separate pieces, each
suitably insulated from the other, which arrangement we employ for multiple
connections or for boards connected in multiple sories, whereby we are enabled to
accommodate a great number of subscribers in a small or compact space and to
meet the requirements as to the control by an operator of a large number of jacks,.
which is an essential requisite of an effective board according to the present
systems and thus our invention is adapted to meet such present requirements.
We will now proceed to describe the construction of the jack proper that is the part
of the commutator board adapted to receive or prepared for the reception of the plug.
According to our invention we arrange or adapt the ordinary two or five point
or any existing form of jack in connection with our commutator board, provided
with or without the usual continuation pieces or accessories as may be required.
Any suitable form of test click arrangement may be employed in connection.
with our board.
Each metallic section or subsection in each commutator" throughout the whole
series is suitably connected together by means of suitable wiring, that is, the said
becue forming the inner sides of the "commutator" as herein first described arc
each counected to the operator's switch so as to form a complete circuit when
subscriber's plug-hereinafter described is inserted in the jack or between tho
space intervening between the said sections, that is, in the hollow form or case-liko
conimutator."
We will now proceed to describe the construction of plug.
In order to effect a communication between two jacks we assign two or a pair
of pluge, the plugs used throughout the board are facsimiles of each other
but with certain slight differences which will be hereafter explained; two plugs
are shewn in our illustrations to effect a speech communication between two
persons, or one plug may be employed to accommodate the various and well known
systems in use:
When a pair is employed in any two jacks on the board, a circuit only is effected
thereby with or through the medium of one and the same continuous metallic
section connected throughout the series of "commutators" inter se, by suitable
wiring as before named.
The plug is provided at one end with a handle, its other eud ie. the part.
adapted to enter the jack is provided with metallic contact pieces, and project
beyond the surface of the hollow constructed plug or case. The lengths or extent
of the contact pieces from the handles, of each pair of plugs varies in order to
accommodate and according to the distance of each metallic strip or sub-sectional
strips within the jack that is, from the front of the commutator or face of the
board, so that when the plug is inserted within the jack, contact shall bo made with
two of the sections or sub-sections only, thus a pair of plugs is so adapted to make
contact with the same sections or sub-sections of any two jacks of the commutator
or commutators composing the board, consequently each pair of plugs completes
a circuit through which speech may be transmitted.
The plug has the metallic contact pieces of equal lengths and opposite or parallel
to each other as the metallic sections are two separate pieces and may be situate iu'
juxtaposition to or in line with each other.

page_text: In connection with our invention any of the well known systems for ringing may
be employed. If a system of ringing be employed which involves the ringing of
the subscriber by the operator we employ two coloured ringing keys provided so
as to correspond with the coloured handles of each pair of plugs, that is, one may
be for example black the other white.
This is accomplished by connecting with a suitable ringing apparatus which may
be of any ordinary construction, which ringing apparatus is suitably connected to
certain sections or subsections of the metallic strips of the commutator which
ringing connections are so arranged that either one of any two subscribers shall
be rung up at any time at the discretion of the operator by the insertion in the
jack of a black or white-handled plug.
In order that our invention may be clearly understood we have reference to the
accompanying sheets of drawings in which like letters of reference indicate iiko
parts throughout the various figures therein shown.
Figure 1 is a plan showing the commutator board in section.
Figure 2 is an elevation of Figure 1.
Figure 3 is au end sectional view of Figure 2.
Figure 4 is a plan of the commutator drawn to an enlarged scale showing the
metallic strips subdivided into or composed of parts.
Figure 5 is an end view of Figure 4.
Figure 6 is a view drawn to an enlarged scale showing the individual parts from
which the metallic strips in Figure 4 are built up or composed.
Figure 7 is an end view of the parts shown in Fig. 6.
Figure 8 is a view showing the form when the parts are placed together in
position as shewn in Figure 4 which position shows the firin of a subdivided
metallic strip.
Fig. 9, is an end view in section of a plug within the jack.
Figs. 10, 11, 12, and 13, are views shewing a plug in detail; Fig. 12,, shews the
upper part of the plug case removed.
the
Fig. 14, is a cross section of plug through A, B.
Fig. 15, is a front view of the sectional strip shewing the complete insulation of
parts.
Fig. 15 is a diagram shewing the complete connections of operators instruments
with the commutator sections, plugs, and jacks.
Fig. 16, is a diagram shewing the completo connections of operators instruments
with the commutator, plug, aud jack of a trunk board.
The commutator is built up or formed of pieces of ebonite, a, placed together in
any number, or series one above the other, which we provide with strips of metal b,
in grooves or otherwise lengthwise of the ebonite pieces. At equal distances
throughout the length of the ebonite pieces a, we employ ebonite divisions, parts,
or pieces c, between which spaces e are formed, thus forming openings or entrances
to the jacks proper marked e, in which the plugs d, are to be inserted two pairs of
which plugs are inserted in position as shewn in Fig. 1. The jacks e,-which may
be any ordinary form of jack, i.e., a two or five point jack, which forms are well
kuown-are situate at the back portion of the commutator.
Fig. 4, represents another form of commutator which varies from the form shewn
in Fig. 1, as the metallic strips are in this figure shewu subdivided into three
pieces f, g, h, which parts are insulated from each other by spaces and lengthwise
of the strips by insulating pieces i. The plugs d are formed or adapted to pass
within the openings or entrances to the jacks, the said plugs have hollow or case
like stems in which enter and are situate two metallic contact pieces; each
provided with contact points respectively one contact point is situate at or
projects above the upper part of the plug stein and the other is situate below which
pieces are of equal or unequal lengths see Figs. 10, 12, 154, and 16, or the contact
pieces may be on one side in the case where the commutator sections are in line
see Fig. 5.
The metallic pieces';;' are attached by means of screws k, to the plates or flat

page_text: which
portions of the metallic sides I, which extend into the handle of the Pg. 10;
part is composed of ebonite and which construction is clearly shown in
the pieces so attached to the metallic pieces 1, thus form-when contacts
made in the commutator-a circuit from to or from or to as the case
may be. Figure 12, also shews the cover or upper part d' of the plug removed in
order to shew the details in elevation. Fig. 13, shews the sectional elevation of
the plug, but the lower metallic contact point only. The upper metallic
sections of the commutator may be wired by wires m, and the lower sections by
wires, which connect in series the upper and the lon or metallic sections
respectively with the operators switch.
The general operation of our invention is as follows
The person operating will have under control or for disposal pairs of plugs
on the table, the number of pairs will be in proportion to the number of jacks
allotted to the operator the board being provided with a number of jacks corre-
sponding to the number of subscribers as 'is now the case, as the jacks on ench
board may be connected together in multiple series or in any suitable manner.
The operator on answering a subscriber's call will pull over a switch, any switch
which is not in use may be used, then take up one of the pair of plugs in proximity
to the switch so pulled over, aud insert it in the subscriber's jack making the call,
then take up the other plug and insert it in the subscriber's jack whose number is
asked for.
But on first inserting the plug in the subscriber's jack whose number is asked
for, the said plug being of suitable form and proportion, the plug on being com-
pletely inserted within the jack proper marked e, the metallic siles . make contact
at with the jack or line pieces e, the speaking current then passes through the
metal sides, which terminate in the form of plates in the handle of the plug the
current is then conveyed through the pieces j screwed to the plates of the metal
sides, see Fig. 10, then out at points and along the metallic strips of the
commutator with which the points may be in contact which strips are suitably
wired and connected with the operators instruments as in Figs. 1, and 2, the current
then passes out at the contact points of a plug on a corresponding section or
sections as in the case of the plugs marked 1, 1, then thro. sides I, out at of
plug 1, to jack e. The corresponding pair marked 1, 1", make contact with the
same or corresponding strips top and bottom i.e. see Fig. 3, j, also the plugs
marked 2, 2*, make contact with the same or corresponding strips, thus a speaking
communication is opened on and through the same continuous metallic sectious
with which sections two persons only can speak thro. the medium of a pair of plugs
as the contact point or points make contact with one or the same metallic section
made continuous by wireing as before fully described and which pair of plugs
complete the speaking circuit.
We would have it understood that our apparatus may be used or applied in
connection with call wire or other systems now in use.
Fig. 15 illustrates our invention connected with the ordinary operators instru
ments or accessories which figure is a diagram illustrating the ringing circuit also
illustrates the speaking circuit the positions of the keys or contacts represent the
subscribers line open to the operator.
The figure shews two plugs the one C. may have a black handle the other D
may have a white colored handle auch pair so arranged, form two speaking and
ringing plugs, the said plugs have their contact points ou contact pieces of
different lengths but such as to make contact with three sections 6 6 6 of the
commutator, the plugs are shewn making contact at with the jacks e, the
connecting wires E EE' pass from the cominutator sections to the listoning key F,
the receiver and usual accessories at G. The connections, keys, or contacts at D
when operated to the positions as shewn in dotted lives form a ringing circuit
through the plug D and between D and C, the connections, keys, or contacts at C
when operated to the positions as shewn in dotted lines forin a ringing circuit
B

page_text: through the plug, C, and between C and D, which circuits may be readily traced.
by reference to the diagram.
The connections for speech communication is shewn to be formed through the
wires E E E the positions of the contact points being then as shewn in dotted
lines at F (listening key) which also shews the ring off indicator II in circuit.
This invention is particularly important for use in trunk exchangas, as by its
use the operation of connecting subscribers or trunk and junction lines, will be
greatly facilitated, as one plug will only be required for such purpose as by means
of the construction of the conmutator jack the operator's switch performs the office
of a jack and plug.
The application of our invention for the above purpose that is for use in 0901-
nection with trunk and junction lines is shewn in Figure 16 and is as follows:-
"
The trunk line I is connected with or put in circuit with a suitably constructed
operator's switches J and K whioh switches are as shewn in the figure in their
normal position i.e. in circuit with the wires or connections L of each "commutator'
strips or metallic sections 6 of the switchboard, and which operator's switch is also
in circuit with the usual accessories such as annunciators M.
The operation of this part of our invention is as follows:-
When a signal is sent from the Trunk Office, line I that is, from the office having
the control of the trunk lines or inter-town connections, for example from a centre
such as H. M. Post Office, to the Telephone Exchange centre, which centre hins
the coutrol of the junction lines or subscriber's wires P and which trunk lines are
extended from the Post Office switchroom to the Exchange centre, the annunciator
drops in the Exchange switchroom, the operator upon receiving instructions from
the trunk office to connect any particular trunk with a subscribers or junction line,
operates to the position of douted lines the switch N or O which form the ringing
circuits of the trunk and junction or subscribers line P respectively thus puts the trunk
line in circuit with the "commutator," inserts the plug in a jack, being the number
of the subscribers jack asked for as the subscribers in the Exchange are distributed
on the board, operates the switch or listening key J to position of the dotted lines
thus a through communication for purposes of speech is opened between the two
persons on the trunk and junction lines and such is accomplished by the use of one
plug and the operator's switch at J. It will be manifest that the operation is
similar in the event of the Exchange requesting through connection on the trunk
lines, that is, from the Telephone Exchange to the Trunk Office.
We have now fully stated he nature of our invention, speech may thus be
effected without the aid or employment of cord-like or Hexible and fibrous or textile
covered plug connections or attachments as now employed which parts or connections
have been found in practice to become defective and productive of faults due to
faulty connections as the fibrous or other coverings of the wire plug connections
become by use worn, thus exposing or laying bare the wires, hence the abnormal
contacts during manipulation of the plug in the switch room with somu metallic or
conducting surface of the plug, consequently interruptions of speech or the creation
of faults as before named results, which it is the sole object and purpose of this our
invention to remedy, and which we claim to accomplish by the means hereinbefore
set forth in the foregoing description.
Having now particularly described and ascertained the nature of our said iuven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In a telephonic or telegraphic switchboard in combination a series or number
of ebonite or non-conducting pieces a, provided with strips of metal b, divided by
division pieces c, forming a commutator, the plug d, and the jack e, substantially as
and for the purposes herein set forth.
2. The subdivided strips as shewn in Figures 4 and 6 as and for the purposes
herein set forth.

page_text: 3. The plug d having metal sides 4, and provided with spring or contact
pieces of the form as shown in Fig. 12 or in Figuro 5 or of the form as shewo
in Figures 15 and 16, projecting through the plug case as and for the purposes
herein set forth.
4. The combination of the jack e the line pioces the spring contact pieces j, j'
and the commutator strips b, as and for the purposes herein set forth.
5. In combination the line pieces 1, and the spring contact pieces jj' of the plugs.
as and for the purposes herein set forth.
حممد
CHAS. SHORE.
CHAS. HEAP.