Improvements in Telephone Circuits.
Year: 1892

page_text: Date of Application, 15th Nov., 1892
Complete Specification Left, 15th Aug., 1893-Accepted, 28th Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in Telephone Circuits.
GEORGE LEE ANDERS, Electrician, of 10 Jeffrey's Square, London, E.C. and
WALTHER KOTTGEN, Merchant, of 10 Jeffrey's Square, London E.C. do hereby
declare the nature of this invention to be as follows:-
The nature of this invention dispenses with the necessity of the use of a battery
and an induction coil at each station for the working of a group of telephones,
and consists in providing one induction coil and one battery only for the general
use of a number of stations in a given group of telephones. Thus in wiring an
hotel or other large building a battery and induction coil is located at a convenient
point. From these run the primary and secondary wires to each station, so that
each and all of them can use the same battery and induction coil. In induction
systems it as hitherto been usual to provide an induction coil and local battery at
each station, whereas by this invention the necessity of doing so is dispensed with,
a suitable automatic connection being provided in the telephone to connect the
various circuits.
Dated this 14th day of November 1899
GEO. L. ANDERS.
WALTHER KOTTGEN.
COMPLETE
SPECIFICATION.
Improvements in Telephone Circuits.
GEORGE LEE ANDERS, Electrician and WALTHER KOTTGEN, Merchant, both
of 10 Jeffrey's Square, St. Mary Axe, in the City of London 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 :-
The object of this invention is to provide a system of circuits for a group of
telephouic stations which are comparatively near together, such as may be found
in hotels, offices, and private houses etc. This system provides for speaking with
an induction current between any of the stations in a group, with one induction
coil, and one battery only, which may be located at any convenient point in the
system, thus avoiding the inconvenience and greater cost of using a local battery
and induction coil at each station.
The speaking current being an induced current, it will be seen that this system
admits of being connected with distant groups of telephonic stations in which
induction currents are used, or with a "telephonic exchange" in which such
currents are generally used.
As this arrangement of circuits admits of the use of most of the well known parts
and devices for telephones in general use, it is deemed sufficient to give a
diagramatic drawing of four stations only, but it will be readily seen, how the
same may be extended, or connected to distant groups of telephonic stations, or to
a "telephone exchange."
The accompanying diagram shows four stations, No. I being a central station
where connections may be made between itself, and any other station, and con-
nection may also be made at No. I station between any other two stations of the
group which may desire to speak with each other. It will be seen that the battery
and induction coil are located at station I, but they may be placed at any point
between the primary wire which traverses each station, and the returu wire from
each, or between primary wire and earth, if the earth be used at each station.

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page_text: receiver. Sometimes this is necessary to prevent overhearing at station 1. The
circuits established between station II, and station III will be as follows:
Station II, when pressing the ringing key K¹, starts a current from battery B,
through the primary of the induction coil C, battery wire, contact 5¹, key K', line
wire to the plugs P₁; by these it passes to line III, to station III, ringing the
bell G, returning to the opposite pole of the battery by return, or earth. It will
be seen, that when the plugs P₁ are inserted between lines II and III, there is
also an alternative circuit from the plugs through the secondary to return or earth
wire, but it is evident, that any direct battery current, transmitted by either of
the two stations thus connected, will not materially weaken the ringing of the
bells G and G, by passing through the secondary induction coil wire. The two
stations having removed their respective receivers for speaking, the secondary
current will traverse the following circuits: from point 8, station I, through the
secondary of induction coil C, by the cord of plugs P¹, where it will split, and
divide between the two line wires II and III, passing through their respective
receivers to the return wire, or earth. The primary circuit will be from battery B
through induction coil C, then splitting at point 6 between the microphones M'
and M at stations II and III, returning to the opposite pole of the battery, as
already described.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:
Claim 1. Two or more telephonic stations in combination with a single battery,
and a single induction coil, placed at any convenient point in its circuit, with a
wire running therefrom to all the stations, so that each station is enabled to use
the same battery and the same induction coil to generate the induction current
for speaking with one another.
Dated the 14th day of August 1893.
GEORGE LEE ANDERS.
WALTHER KOTTGEN.