Improved Means of Inter-communication by Telephone.
Year: 1893

page_text: Date of Application, 2nd Oct., 1893
Complete Specification Left, 2nd July, 1394-Accepted, 1st Dec., 1894
FIOVIDIONAL SITIORTION
Improved Means of Inter-communication by Telephone.
1 JOHN JAMES MANN of Peel Mills Adelphi Salford in the County of
Lancaster, Electrician, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to make an automatic telephone system, that is to
say a system by which any member of any number of subscribers to a telephone
exchange can communicate with any other member without the intervention of an
operator at the exchange.
For this purpose I make use of a complete metallic circuit but I break the same
in four places, two at the exchange and two at the subscriber's instrument, and by
taking each of the wires at each of these points to earth I so make use of three
distinct circuits; namely the metallic circuit itself, the one side of the metallic
loop earthed at both ends, and the other side of the metallic loop earthed at
both ends.
The two latter circuits can be utilized for working the switch at the exchange,
and the metallic circuit for speaking.
Dated this 30th day of September 1893.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Means of Inter-communication by Telephone.
1 JOHN JAMES MANN of Peel Mills Adelphi Salford in the County of
Lancaster, 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 :-
The object of this invention is to make an automatic telephone system, that is to
say a system by which any member of any number of subscribers to a telephone
exchange can communicate with any other member without the intervention of an
operator at the exchange.
For this purpose I make use of a complete metallic circuit but I break the same
in four places, two at the exchange, and two at the subscriber's instrument, and by
taking each of the wires, at each of these points to earth, I so make use of three
distinct circuits; namely the metallic circuit itself, the one side of the metallic
loop earthed at both ends, and the other side of the metallic loop earthed at
both ends.
The two latter circuits can be utilized for working the switch at the exchange,
and the metallic circuit for speaking.
In order that my invention may be more clearly understood I have annexed
bereunto two sheets of drawings illustrative thereof.
Fig. 1 Sheet 1, is a diagram showing how the circuits are formed. On
Sheet 2, Fig. 2 is a transverse section, Fig. 3 a side elevation and Fig. 4 a plan

page_text: of an arrangement of automatic switch, which can be placed at the exchange and
worked from the subscriber's premises.
Referring to Fig. 1 a represents the complete metallic circuit, a¹ represents a
point at the exchange and at the subscriber's instrument. The metallic circuit a is
broken in the four places shewn at 1, 2, 3, 4, by the wires c, c', b', b, each of which
is taken to earth at E. A switch is provided at or near 1 and 4 so that when the
circuit a has been interrupted, say, by the ordinary automatic switch actuated by
the subscriber's receiver as usual, the wire c can be connected thereto and a
circuit E, c, a, c', E obtained. In the same way a circuit E b, a, b, E can be
obtained.
Either or both of these last named circuits can be utilized to actuate a mechanical
switch at the exchange by alternately interrupting and completing the said circuit
or circuits. This will switch the subscriber on to the required wire instead of
employing an attendant at the exchange.
The
The switch being thus adjusted the metallic circuit a may be completed.
mechanical switching mechanism is thus "cut out" and the circuit a can be used in
the ordinary way for speaking.
For example when the circuit E ca e E is employed for working the switch at
the exchange, an ordinary switch may be employed at d, see Fig. 1, between the
point 1 and the earth, and at the exchange, the wires connected with the other
subscribers' premises may be arranged in a circle, as seen at Figs. 2, 3, 4, in which
ten wires only are shown for the sake of simplicity of illustration; and the switch
may be in the form of a rotating finger or spring which can be set to make
contact with any of the points of connection 1 to 10.
The wire c¹, before passing to a battery and thence to earth, is passed to the coils
of an electro magnet e, see Figs. 2, 3, and 4 the armature of which is on a catch
lever provided with two catches f₁f acting as an escapement on the ratchet
wheels g', which are worked together by the gearing 9, 9', the wheel g' being
fixed on, or connected to a spring barrel 9 which has a constant tendency to revolve
in the direction of the arrow. The speaking circuit a being interrupted by hanging
up the receiver on the switch hook as usual, every time that the circuit cac is
completed by the switch at d the barrel will revolve the distace of half a tooth of
the wheel because the weighted catch will be raised and release the wheel g¹;
the wheel 9 will be stopped however by the catch f; on releasing the switch d the
wheels g¹ 9 will revolve for one more half tooth and the switch which carries
the two wires of the circuit a will be connected with one of the points 1, 2, 3, 4, &c.
on each of which are carried the wires of another subscriber. The first contact
by the switch & thus takes the wires on the switch to the wires of No. 1 circuit,
the second to the wires of No. 2 circuit and so on. Having arrived at the required
number, the working of the switch d is stopped and the receiver can be removed
from its hook, and the speaking circuit will be completed and the switching
mechanism and the earth circuit will be "cut out." The circuit b', a, b may be
used to return the switch to the point 0 or to ring a bell, or for any other desired
purpose. The switch may however be returned to the point O by hanging
up the receiver and continuing its revolution by the switch d. It will be found
preferable to use a counter or indicator in the subscriber's room to shew how
many times the switch d has been worked, and thus indicate the position of the
switch ..
If preferred the metallic circuit a can be used for working the mechanical switch
and one of the other circuits for speaking.
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:
:-
In an automatic telephone system a complete metallic circuit for inter-com-
munication by telephone broken in four places; two at the exchange and two at

page_text: the subscriber's instrument, each of the wires at each of these points being taken to
earth, whereby I make use of three distinct circuits, substantially as and for the
purposes hereinbefore described.
Dated this 30th day of June 1894.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.