Improvements in Telephonic Apparatus for Simultaneous Telegraphy and Telephony on the same Line Wire.
Year: 1895

page_text: Date of Application, 3rd Jan., 1895
Complete Specification Left, 2nd Oct., 1895-Accepted, 23rd Nov., 1895
Improvements in Telephonic Apparatus for Simultaneous Telegraphy
and Telephony on the same Line Wire.
⚫I GEORGE HENRY BASSANO of No. 23 Lodge Lane Derby Manufacturing
Electrician do hereby declare the nature of this invention to be as follows:-
As is well known the ordinary telephone currents when transmitted upon an
ordinary telegraph circuit do not interfere with the working of the telegraph
apparatus because the electric currents from the telephone are of a rapid undulatory
character and do not have time to move the ordinary comparatively slow moving
polarised needles or armatures of the telegraph apparatus the reversed undulations
following each other too quickly for the needles or armatures to respond. On the
other hand the telegraph currents used in ordinary telegraphy are comparatively
of low intensity and large quantity and intermittent or intermittently reversed in
character and have little or no effect upon a telephone through a condenser of
fairly low capacity say of one half or one microfarad. On the other hand the
telephone currents act equally well through such a condenser.
A retardation coil of suitable resistance in the telegraph circuit between the
telegraph apparatus and the condenser in shunt therefrom for the telephone further
reduces the disturbing effect if any of the telegraph currents upon the telephone
through the condenser.
It will be obvious therefore that the ordinary method of calling attention on the
telephone by pressing a key and thus sending the ordinary battery current (which
is an ordinary telegraph current) to line to ring a small trembling bell at the
opposite end is not available for a telephone call for simultaneous telegraphy and
telephony on the same line wire.
The usual method has been to use a rapid alternating or undulatory current by
passing a rapid intermittent current through the primary circuit of an induction
coil which induces a rapid alternating current of high intensity in the secondary
coil and which therefore acts well through the condenser and is available to give
out a musical note in a suitable receiver to act as a call or to ring a bell through a
relay having a coil suitably wound to be sensitive to the low quantity and high
intensity of the alternating current.
The objection however to this call is that in passing through or along the line
wires a corresponding current is induced in neighbouring wires and if they are
telephone wires the disturbing effect of this high musical note is very objectionable
to those using the latter telephones.
The object of this invention is to overcome this difficulty by making the
telephone used in combination with condensers sufficiently loud to obviate the
necessity for this high pitched musical note to call attention the mere calling of
the individuals name or the station into the telephone being sufficient to be easily
heard in the room in which the apparatus is fixed. "This I propose to do by using
the loudest telephone receivers obtainable with a trumpet or resonator thereon to
magnify or amplify the sounds; by using a transmitter such as the "Hunning's
transmitter which may be spoken into loudly without actually breaking the primary
circuit or interupting the continuity of the primary current as is done if a
transmitter with only one or two contact points is used; and by so arranging the
circuit connections as to overcome the retarding effect of the induction coil being

page_text: in circuit with the receiver at the receiving end; and at the same time by means of
condensers to only use the ordinary telegraph wires.
There are usually two or more ordinary telegraph wires available upon any
railway or Government line of poles and propose to utilise these as follows-
At each of two stations I propose to fit two condensers of low capacity in one
telephone case each perfectly independent of the other. One terminal of one
condenser would be attached to one line wire and the other to the secondary coil of
the telephone induction coil the other end of the secondary coil being to earth or
attached to a third wire as return.
The second condenser would be attached by one terminal to the second line wire
and by the other to oue terminal of a loud telephone receiver and thence to earth
or to the before mentioned third wire as return. In joining up two such instru-
ments as these to the line wires I propose to attach them thereto so that the
condenser with transmitter is placed upon one wire at one end and on the same wire
at the other end the condenser with the receiver so that the secondary coil of the
induction coil is never in circuit at the receiving end of either. The retarding
effect of the induction coil upon the incoming current at the receiving end is very
great and greatly reduces the sound of the telephones in consequence. This
removes the difficulty, and I sometimes do this in a condenser telephone arranged
in the ordinary manner by placing the induction coil in shunt or parallel with the
receiver so that the currents in passing through are split. This of course is not so
good an arrangement but is better than both being merely in series. The other
parts of the circuits in the apparatus are so arranged that the primary circuit of
the induction coil is broken down when not in use, either in the ordinary way by a
switch hook upon which a receiver is hung when not being used or by a key or
button or switch having to be held to join the circuit up whilst being used and
which breaks the circuit again when done with by being released or it may be done
by any other equivalent means the secondarys always being in circuit ready for
receiving. In this arrangement with two condensers in each instrument I also
propose if required to fix retardation coils (ordinary electro magnets with good
sized soft iron cores) in the telegraph line wires.
I also propose to use if there are any intermediate telegraph instruments on the
circuits to bridge them over from line terminal to line terminal by a condenser or
condensers of suitable capacity so that the telephone currents may pass along
without interruption or interferance.
Of course where there is no objection to the high pitched musical note for calling
attention on the telephones through there being no other telephone wires on the
same poles or adjacent to the wires made use of I may use this combination of two
condensers with receiver and transmitter on different wires for loud speaking in
connection with such a call. The object of the arrangement is principally to
increase the loudness of the sounds transmitted and received telephonically so that
I may either do with or without a call arrangement for use in noisy places where
loudness is practically a necessity.
Dated this Second day of January 1895.
Improvements in Telephonic Apparatus for Simultaneous Telegraphy
and Telephony on the same Line Wire.
GEORGE HENRY BASSANO No. 23 Lodge Lane Derby Manufacturing
Electrician 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 :-
As is well known the ordinary telephone currents when transmitted upon an.

page_text: ordinary telegraph circuit do not interfere with the working of the telegraph
because the electric currents from the telephone are of a rapid undulatory character
and do not have time to move the ordinary comparatively slow moving polarised
needles or armatures of the telegraph apparatus the reversed undulations following
each other too quickly for the needles or armatures to respond. On the other hand
the telegraph currents used in ordinary telegraphy are comparatively of low
intensity and large quantity and intermittent or intermittently reversed in character
and have little or no effect upon a telephone through a condenser of fairly low
capacity say of or 1 microfarad. On the other hand the telephone currents act
equally well through such a condenser. A retardation coil of suitable resistance
in the telegraph circuit between the telegraph apparatus and the condenser in shunt
therefrom for the telephone further reduces the disturbing effect if any of the
telegraph currents upon the telephone through the condenser. It will be obvions
therefore that the ordinary method of calling attention on the telephone by pressing
a key and thus sending the ordinary battery current (which is an ordinary telegraph
current) to line to ring a small trembling bell at the opposite end is not available
for a telephone call for simultaneous telegraphy and telephony on the same line
wire. The usual method has been to use a rapid alternating or undulatory current
by passing a rapid intermittent current through the primary circuit of an induction
coil which induces a rapid alternating current of high intensity in the secondary coil
and which therefore acts well through the condenser and is available to give out a
musical note in a suitable receiver to act as a call or to ring a bell through a
relay having a coil suitable wound to be sensitive to the low quantity and high
intensity of the alternating currents. The objection however to this call is that in
passing through or along the line wires a corresponding current is induced in
neighbouring wires and if they are telephone wires the disturbing effect of this high
musical note is very objectionable to those using the latter telephones.
The object of this invention is to overcome this difficulty by making the
telephones used in combination with condensers sufficiently loud to obviate the
necessity for this high pitched musical note to call attention, the mere calling of
the indviduals name or the station into the telephone being sufficient to be easily
heard in the room in which the apparatus is fixed. This propose to do by using
the loudest telephone receivers obtainable with a trumpet or resonator_thereon
to magnify or amplify the sounds; by using a transmitter such as the Hunnings
transmitter which may be spoken into loudly without actually braking the primary
circuit or interupting the continuity of the primary current as is done if a
transmitter with only one or two contact points is used; and by so arranging the
circuit connections as to overcome the retarding effect of the induction coil being
in circuit with the receiver at the receiving end; and at the same time by means of
condensers to only use the ordinary telegraph wires.
There are usually two or more ordinary telegraph wires available upon any
railway or Government line of poles and propose to utilise thse as follows:-
At each of two stations I propose to fit two condensers of low capacity in one
telephone case each perfectly independent of the other. One terminal of one
condenser would be attached to one line wire and the other to the secondary coil
of the telephone induction coil the other end of the secondary coil being to earth
or attached to a third wire as return. The second condenser would be attached by
one terminal to the second line wire and by the other to one terminal of a loud
telephone receiver and thence to earth or to the before mentioned third wire as
return.
In joining up two such instruments as these to the line wires I propose to attach
them thereto so that the condenser with transmitter is placed upon one wire at
one end and on the same wire at the other end the condenser with receiver so that
the secondary coil of the induction coil is never in circuit at the receiving end of
either.
The retarding effect of the induction coil upon the incoming current at the

page_text: receiving is very great and greatly reduces the sound of the telephones in
consequence:
This removes the difficulty and I sometimes do this in a condenser telephone
arranged in the ordinary manner by placing the induction coil in shunt or pirallel
with the receiver so that the currents in passing through are split. This of course
is not so good an arrangement but is better than both being in series.
The other parts of the circuit in the apparatus are so arranged that the primary
circuit of the induction coil is broken down when not in use either in the ordinary
way by a switch hook upon which a receiver is hung when not being used, or by a
key or button or switch having to be held to join the circuit up whilst being
used and which breaks the circuit again when done with by being released, or it
may be done by any other equivalent means the secondary always being in circuit
ready for receiving.
In this arrangement with two condensers in each instrument I also propose if
required to fix retardation coils (ordinary electro magnets with good sized cores of
soft iron) in the telegraph line wires.
I also propose to use if there are any intermediate telegraph instruments on the
circuits to bridge them over from line terminal to line terminal by a condenser
or condensers of suitable capacity so that the telephone currents may pass along
without interuption or interference.
Of course where there is no objection to the high pitched note for calling
attention on the telephones through there being no other telephone wires on the
same poles or adjacent to the wires made use of I may use this combination of two
condensers with receiver and transmitter on different wires for loud speaking in
connection with such a call.
The object of the arrangement is principally to increase the loudness of the
sounds transmitted and received telephonically so that I may do either with or
without a call arrangement for use in noisey places where loudness is practically a
necessity.
And in order that my invention may be better understood I will now proceed to
describe the accompanying drawings in reference thereto.
Fig. 1 shews one method of joining up in which three wires are made use of.
It is supposed that three wires run without a break or intermediate block or other
telegraph instrument between station A. and station B.
T and Tare two block or other telegraph instruments and at X at both ends an
ardinary electro magnet with thick soft iron core may be inserted (but it is not
absolutely necessary) to act as retardation coils to tone down the ordinary
telegraph currents made use of and also to retard the passage of the undulatory
telephone currents through the ordinary telegraph instruments so that the
condensers C¹ C1 C2 C2 may be the more effectually charged by the telephone
currents. At station A C₁ is a condenser of suitable capacity (preferably a
microfarad and upwards) and R is a telephone receiver with one terminal attached
to one terminal of the condenser and the other to wire 2 or earth. At station B.
C' also is a condenser and 1 is the usual telephone induction coil one end of the
secondary wire being joined to one terminal of the condenser and the other end of
the secondary is joined to wire 2 or earth if preferred or if such a wire is not
available.
M' is the microphone B¹ is the battery and K' is a local key or switch to
connect up the microphone to the battery and the primary wire of the induction
coil as shewn,
The parts shewn as connected between wires 2 and 3 are precisely the same as
explained between wires 1 and 2 but in this case the transmitter is at station A and
the receiver at station B. Now it will be seen that when station B speaks to
station A the currents circulate through wires 1 and 2 and that the receiver only is
in circuit at A. with the condenser. The induction coil of A³ instrument being
between the wires 2 and 3.

page_text: On the other hand when station A speaks to B the currents circulate through
the wires 2 and 3 and the induction coil I¹ at B not being in the receiving circuit
does not retard the current. The retarding effect of the induction coil at the
receiving end is therefore by this method of joining up entirely got rid of.
Instead of the wire 2 the earth may be used at both ends with little or no
reduction in the loudness of the sounds transmitted. By this method of using two
condensers in the oue complete telephone one for the transmitting apparatus and
one for the receiving apparatus the connections with the line wire or wires may be
varied in several ways without very much affecting the result. For instance the
third wire as explained may be done without and earth used for the return. Then
they may be connected up to two wires in the manner shewn by diagram in Fig. 2.
In this case transmitter and receiver are joined to the same wire through seperate
condensers at both ends and the opposite terminals of both transmitters and
receivers are joined to the second wire as shewn, or if desired this second wire 2
may be dispensed with and earth used as the return. The effect however in the
latter case is not so good though sufficient for all practical purposes.
In diagram Fig. 2 corresponding letters refer to similar parts fully explained in
describing Fig. 1.
In this case also I wish it to be understood that I am aware that although electro
magnetic retardation coils of suitable resistance may be inserted at X it is not
absolutely necessary as the loudness of the speech transmitted is usually sufficient
to render the sounds due to the ordinary telegraph currents unoticeable.
In case there is an intermediate instrument between A and B which when being
worked would affect the continuity of the circuit or circuits a condenser of suitable
capacity should be fixed as a shunt across the line terminals. It will be obvious
that when joined up as in Fig. 2 any number of instruments within a reasonable
number may be attached to the same line wire.
Having now fully described the nature of my said invention and how the same is
to be performed I declare that what I claim is
First. In an arrangement of simultaneous telegraphy and telephony on the same
line wire or wires the method of joining the transmitter and the receiver substan-
tially as described and set forth in Fig. 1 in combination with condensers in the
manner and for the purpose indicated.
Secondly. The combination in telephonic apparatus for use in simultaneous
telegraphy and telephony on the same line wire or wires of two condensers one for
the telephone transmitter and the other for the telephone receiver substantially for
the purpose and as set forth and described.
Thirdly. The combination of parts in simultaneous telegraphy and telephony on
the same line wire or wires as set forth and described.
Dated this 1st day of October 1895.
GEORGE HENRY BASSANO.