Improvement in Combined Telephony and Telegraphy.
Year: 1889

page_text: Date of Application, 14th May, 1889-Accepted, 13th July, 1889
COMPLETE SPECIFICATION.
Improvement in Combined Telephony and Telegraphy.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention (which has
been communicated to me from abroad by James Hart Robertson, Electrician,
residing at the corner of Sylvan Street, and The Terrace, Rutherford, Bergen County
New Jersey, United States of America,) 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 my invention is to utilize the circuit of the autographic telegraph
for which United States Letters Patent No. 353,593 dated November 30. 1886,
were granted to the above named James Hart Robertson, for telephonic purposes,
in such manner that both the telegraphic and the telephonic instruments can be used
simultaneously without interference with each other. 1 accomplish this object by the
means hereinafter described and claimed. The accompanying drawing forming part
of this specification illustrates a combination of parts euibodying my invention.
In said drawing I have shown two line wires connecting the autographic instruments
of separate stations, but if desired, only one line wire may be used, as described for
example, in U.S. Patent No. 353,541 dated November 30, 1886.
My present invention is adapted to both arrangements, though the one illustrated
is preferred.
Referring to the drawing, 1 and 2, designate the lines wires in which the trans-
mitters 3, and receivers 4, of the autographic telegraph are inserted. The transmitters
consist in part of piles of carbon disks, as fully described in the patent herein before
referred to, and the receiver may be also of the construction therein shown, or of any
other suitable construction. The two line wires are connected at each end to a single
ground wire 5, and the batteries 6 and 7, are of equal strength and have their like
poles opposed to each other as fully described in the application herein before
referred to.
:-
I combine the telephonic apparatus with the telegraphic circuit in the following
manner wind the secondary wire 8, of the induction coil 9, around both the
electro-magnets of the telegraphic receiver 4. In said secondary circuit is placed
telephonic receiver 10; the transmitter 11, and battery 12, being located in the
primary circuit 13 as usual. It is not essential that the secondary wire 8 be wound
around both electro-magnets, for it may be wound around only one of them, though
better results may be obtained when wound around both as shown.
As in using the autographic telegraph the circuit is never broken, but merely
increased or decreased in resistance, thus decreasing or increasing the strength of the
current, it is clear that there is at all times an unbroken circuit for an induced
current of electricity. This induced current will pass through the transmitters and
receivers of the autographic telegraph without affecting them, i.e. without interfering
with the battery currents. It will also be observed that any changes which take
place in the strength of the current flowing in the line due to the operation of the
telegraphic instruments cannot in the least affect the telephonic instruments, for the
reason that such changes are made gradually.
At 14, I have shown a switch which is preferably closed for evident reasons when
writing is not being done. I have shown switches in only one line, but they are preferably
used in both. It will be apparent without further explanation, that the autographic
telegraph and the telephone may be used simultaneously on the same line wire
or wires, without any interference with each other, for the reasons hereinbefore
stated.

page_text: Having now particularly described and ascertained, the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. The combination with an autographic telegraph, of a telephone, the secondary
circuit of which is arranged in inductive proximity to the receiver electro-magnets of
the autographic telegraph, substantially as described.
2. The combination with an autographic telegraph, of a telephone, the secondary
circuit of which is arranged in inductive proximity to said autographic telegraph,
substantially as described.
Dated the 1
1000
ALLISON BROS.,
Agents for the Applicant.