Improvements in Duplex Telegraphy.
Year: 1888

page_text: Date of Application, 2nd Feb., 1888
Complete Specification Left, 15th Oct., 1888
Complete Specification Accepted, 16th Nov.. 1888
PROVISIONAL SPECIFICATION.
Improvements in Duplex Telegraphy.
I, FRANK JACOB of 12 Queen Anne's Gate Westminster in the County of Middlesex
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
In order to obtain a perfect balance between the artificial and the actual cable it is
necessary that every electrical quality and circumstance of the latter should be
reproduced as closely as possible in the former.
Now, for the better convenience in handling the traffic on a Submarine Cable, it
often happens that the operating station is situated at some distance from the shore
end of the cable, and connection thereto is made by an underground wire, or cable, or
other suitable conductor, and further a second underground wire, or cable, or other
suitable conductor, is used for the earth connection from the said operating station,
the earth being usually formed by the sheathing of the cable, though in some cases by
any other adequate connection to the ground; such conductor between the station
and the ground connection or sheathing of the cable, I term an "Earth Cable."
In such case, therefore, namely when an earth cable is employed I introduce, for
the purpose of establishing a perfect duplex balance, between the earth-armature of
the artificial Cable and the end of the conductor of the earth-Cable at the operating
station, an artificial line or cable similar in all its electrical qualities to the said Earth-
Cable.
I may here explain that an artificial Cable consists of two sets of conducting plates
separated by a dielectric, the one set forms the conductor equivalent in resistance to
that of the actual cable, either by being suitably shaped and connected in series, or by
the interpolation of suitable resistances between each plate or component group of
plates; the other set of plates are connected together and form what I term the
earth armature" of the artificial cable.
I sometimes find it advantageous, in combination with the above arrangement, to
ntroduce an adjustable condenser with one of its terminals connected at some point

page_text: along the bridge arms or at a point near the junction of the one arm of the bridge
and the Cable, and its other terminal connected to the Earth Armature of the artificial
Cable at that portion of the artificial Cable which is connected to the bridge arm.
I know that it has been usual to introduce such a condenser with one of its
terminals connected at some point along the bridge arms and its other terminal con-
nected to earth or to the earth-Cable, either direct or through a separate resistance,
such resistance not forming part of any other circuit. My improvement consists in
connecting this last mentioned terminal of the said condenser to the earth armature of
the artificial Cable at that portion of the artificial cable which is connected to the
bridge arm, so that this last mentioned terminal of the said condenser is connected
to earth through identically the same circuit as the earth armature of that portion of
the artificial Cable which is connected to the bridge arm.
For the bridge arms in any of the above described arrangements may, of course,
be substituted the coils of a differential wound receiving instrument.
In Figs. 1 and 2 S is the transmitting apparatus, UK is the underground cable,
K the submarine Cable, E K the earth Cable, and A L the artificial Cable.
A. B are the arms of the electrical bridge or the Coils of a differentially wound
receiving instrument.
Rn is the artificial earth cable, R e a resistance representing that of the ground
plate or ground connection.
Rg is a resistance representing that of the soil which surrounds the actual under-
ground Cable.
Cis the condenser introduced between the bridge arm and the earth armature of
that portion of the artificial Cable, which is connected to the bridge arm.
Ris a resistance which has sometimes been introduced for a final adjustment of
balance.
Dated this 2nd day of February 1888.
ABEL & IMRAY,
Agents for the Applicant.

page_text: Improvements in Duplex Telegraphy.
I, FRANK JACOB, of 12 Queen Anne's Gate, Westminster, in the County of
Middlesex, Electrical Engineer, do hereby declare the nature of this invention, and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In order to obtain a perfect balance between the artificial and the actual cables
employed for duplex telegraphy, it is necessary that every electrical quality and
circumstance of the actual cable should be reproduced as closely as possible in the
artificial cable.
Now, for the better convenience in handling the traffic on a submarine cable, it
often happens that the operating station is situated at some distance from the shore
end of the cable, and connection thereto is made by an underground wire, or cable, or
other suitable conductor.
A second underground wire or cable, or other suitable conductor is also used for
the earth connection from the operating station, the earth being usually formed by the
sheathing of the cable, or in some cases by an earth plate or other adequate
connection to the ground.
Such a conductor between the station and the ground connection or sheathing of
the cable I term an "Earth Cable."
In such a case, that is to say when an earth cable is employed, I introduce, for the
purpose of establishing a perfect duplex balance, between the earth armature of the
artificial cable and the end of the conductor of the earth cable at the operating
station, an artificial line or cable similar in all its electrical qualities to the earth
cable itself.
I may here explain that an artificial cable consists of two sets of conducting plates
separated by a dielectric; the one set forms the conductor equivalent in resistancejto
thatof the actual cable, either by being suitably shaped and connected in series, or
by the interpolation of suitable resistances between each plate or component group of
plates; the other set of plates are connected together and form what I term the "earth
armature" of the artificial cable.
I sometimes find it advantageous in combination with the above arrangement to
introduce an adjustable condenser with one of its terminals connected at some point
along the bridge arms or at a point near the junction of the one arm of the
bridge with the cable, and its other terminal connected to the earth armature of
the artificial cable at that portion of the artificial cable which is connected to the
bridge arm.
I know that it has been usual to introduce such a condenser with one of its
terminals connected at some point along the bridge arms and its other terminal
connected to earth or to the earth cable, either directly or through a separate
resistance which does not form part of any other circuit. My invention does not
consist in introducing a condenser in this manner but in connecting the last mentioned

page_text: terminal of the condenser to the earth armature of the artificial cable at that portion
of the artificial cable which is connected to the bridge arm, so that this terminal of
the condenser is connected to earth through identically the same circuit as the earth
armature of that portion of the artificial cable which is connected to the bridge arm.
For the bridge arms in the above described arrangements may of course be
substituted the coils of a differential wound receiving instrument.
Referring to the drawings accompanying my Provisional Specification, in
Figs. 1 and 2, S is the transmitting apparatus, K is the submarine cable, E K is the
earth cable, UK is the underground cable, and A L is the artificial cable.
A B are the arms of the electrical bridge or the coils of a differentially wound
receiving instrument.
Ru is the artificial earth cable, Re is a resistance representing that of the ground
plate or ground connection, R g is a resistance representing that of the soil which
surrounds the actual underground cable.
Of is the condenser introduced between the bridge arm and the carth armature of
that portion of the artificial cable which is connected to the bridge arm.
Rf is a resistance which has sometimes been introduced for a final adjustment of
balance.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In combination with the actual and artificial cables and appliances employed
for duplex telegraphy, an artificial line or cable similar in all its electrical qualities to
the earth cable or conductor connecting the operating station to the sheathing of the
actual cable or to other earth connection, applied and connected as and for the purpose
herein set forth.
2. In combination with the arrangement referred to in the preceding claim, a con-
denser C applied and connected as and for the purpose set forth.
Dated this.15th day of October 1888.
ABEL & INKAI,
Agents for the Applicant.