Improvements in Telephone-circuits.
Year: 1893

page_text: Date of Application, 15th July, 1893
Complete Specification Left, 15th May, 1894-Accepted, 30th June, 1894
Improvements in Telephone-circuits.
I, JÖRGEN JACOBSEN MÖLLER, of Kiel, in the Province of Schleswig-Holstein,
Germany, Postmaster, do hereby declare the nature of my invention to be as
follows:-
This invention relates to improvements in telephone-circuits and the subject of
it is a circuit arrangement for telephone installations, by which during calling up,
the receivers at the transmitting station remain connected with the line wire,
whereby speech is rendered intelligible at the distant station while the key
switching the call bell is held down, without involving any loss in the bell-line
current. By such an arrangement it is also possible to determine at the calling
station whether the bell-signal was received at the other end or whether com-
munication had been interrupted.
The improvement or novelty of the arrangement as adapted for use in an
existing telephone installation on the usual plan, consists in the fact that two of
the three usual contact pieces of the calling device, that is to say, the contact
piece in connection with the line wire and the contact piece connected with the
switching device, are maintained in uninterrupted connection with each other by
means of a suitable conductor whose resistance, however, is considerably higher
than the resistance of the other circuits, so that only a small portion of
the current from the calling battery of the transmitting station to be conveyed
through the respective contact pieces of the calling device to the line wire,
through the switch and thence according as the receiver is suspended on or removed
from the hook of the switch, through the bell circuit or the receiver circuit, reaches
the earth.
On the other hand, however, the current impulses induced by the microphone at
the distant station, after passing through the line wire and the said resistance-
conductor to the switch, may also reach the receiver circuit.
In this arrangement only a portion of the current of the calling battery is
conducted through the receiver circuit, so that the potential of the calling battery
is wholly or in part overcome by the current impulses induced at the distant station.
But the same result may be obtained by conducting the current of the calling
battery in its full strength through the receiver circuit. For this purpose the line
wire is placed in connection with the switch and the said two contact pieces of the
calling device are connected with the receiver circuit and the ground wire
respectively, so that it is not possible for the current coming from the calling
battery to reach the line wire without going through the receiver circuit at the
transmitting station, assuming that the receiver is removed from the hook of the
switch.
In both arrangements, therefore, the receiver-line current at the distant station
is enabled to counteract the bell-line current of the battery at the calling station,
either by its being divided and by conducting the current thus taken off through
the receiver circuit of the calling station, or-assuming the line wire to be in
direct communication with the switch-by its flowing with its full energy through
the receiver circuit. Moreover, if an inductor is placed in the described telephone
installation instead of a signal or alarm battery, the action of the same will remain
unaltered.
Dated this 15th day of July 1893.
PHILIPS & LEIGH,
Agents for the Applicant.

page_text: Improvements in Telephone-circuits.
I, JÖRGEN JACOBSEN MÖLLER, of. Kiel in the Province of Schleswig-Holstein,
Germany, Postmaster, 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 subject of the present invention is a circuit arrangement for telephone
installations, by which during calling up the receivers at the transmitting station
remain connected with the line wire, whereby speech is rendered intelligible at the
distant station while the key switching the call-bell is held down, without involving
any loss in. the bell-line current. By such an arrangement it is also possible to
determine at the calling station whether the bell-signal was received at the other
end or whether any disturbance was present.
In the accompanying drawings in which similar letters denote similar parts two
forms of the above arrangement are diagrammatically shown.
the
In Figure 1 the arrangement is shown as adapted for use in an existing
telephone installation on the usual plan. This arrangement consists mainly of a
microphone M, two receivers F1, F2, a call-bell W, the circuit changer or switching
device A, the induction coil J, the lightning arrester S, and the calling device T.
This latter is provided in the usual manner with 3 contact-pieces s¹, s², s³, of
which the first is attached to the terminal of the bell battery B by the wire a;
contact pieces is in connection with the telephone wire through the wire b and
the lightning arrester S. If the latter, by pressing the alarm-buttom h, is put in
conductive connection with the contact-piece s¹ by means of the contact spring f,
the current coming from the battery B passes into the line wire l, the circuit being
closed by the earth line c and so causing the bell to be sounded at the distant
station. In its normal position, however, the spring rests against the contact piece s³,
so that the line wire by means of the lightning arrester S and the wire is put
in connection with a wire d, leading to the contact-piece 1 of the switch or circuit
changer A. The latter comes into conductive connection with either the contact
piece 3 or 5 according as the receiver F2 hangs on the hook p or not; the contact-
piece 5 puts in circuit by means of a wire e, the alarm bell W, which again is
taken to earth by means of the wires g i. The contact-piece 3 serves, however, to
bring into communication the wire d with the wire k, in which the receivers F1, F2,
as also the induction coil J are placed, and which is taken to earth by the wire c.
The line m, connected to the microphone M, the telephone battery and the induction
coil J starts from the contact-pieces 2 and 4 of the switch A; the circuit is closed
as soon as the receiver F2 is taken off from the switch hook by the action of the
latter upon the plate spring n, which brings the said contact-pieces into conductive
connection with each other.
The arrangement described in the foregoing is the usual one, the novelty con-
sisting in the fact that the contact-pieces $2, $3, are in uninterrupted connection
with each other by means of a conductor w, whose resistance, however, is
considerably higher than the resistance of the circuits referred to as yet so, that
only a very small portion of the current from the battery B of the transmitting
station, is conveyed through the contact-pieces s', f, s2, to the line wire, through the
wire d and the switch A and thence (according as the receiver F2 is suspended on, or
removed from, the hook) through the wires e, g, i, or k, c and reaches the earth.
On the other hand, however, the current impulses induced by the microphone in
the distant station, after passing through the line wire l, the lightning arrester S,
the wire b, the contact-piece s³, the conductor w, the wire d to the switch A, may
also reach the receiver circuit k.

page_text: In the arrangement shown in Figure 2 the line wire and the lightning arrester
are not in connection with the contact-piece of the calling device T, through:
the wire b, but are led to the contact-piece 1 of the switch A, while the contact--
piece ³ is connected to the receiver circuit k, and taken to earth by a wire k'.
The current conveyed by the line wire will then either reach the receiver circuit k,.
or the bell W through the wire e, according as the receiver F is removed or
hangs on the hook p. In the first case the current passes through the calling.
device T, that is to say, through its contact-piece s³, the spring f, contact-piece
and the wires, k³, c, to earth or in the second case through the bell W and the
wires gi. As long, however, as the bell-push his depressed this current, instead of
passing through the wire k', is obliged to go through the wire a, and through
the battery B to earth. It is not possible therefore for the current coming
from the battery B to reach the line wire without going through the receiver
circuit k at the transmitting station, assuming that the receiver F is removed from
the hook p.
The current impulses induced at the distant station by means of the
microphone naturally of a higher potential than that of the battery, are able to.
overcome the current produced by the latter, and to set in motion the diaphragms
of the receivers at the calling station in proportion to the vibrations of the
microphone disc at the distant station.
In both arrangements therefore the receiver-line current at the distant station.
is enabled to counteract the bell-line current of the battery at the calling station,
either by its being divided and by conducting the current thus taken off through
the receiver circuit of the calling station, or assuming the telephone wire to be in
direct communication with the switch by its flowing in its full strength through the
receiver circuit. Also in the event that instead of the signal or alarm battery an
inductor is placed in the described telephone installation, the action of the same
will remain unaltered.
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. In a telephone installation the employment with the contact-pieces and s*
of the bell-push, of a resistance conductor w substantially as and for the purpose
set forth.
2. In a telephone installation, the combination, of line wire l, wire b connecting
the said line-wire with the switch A, receiver-line k, earth-line k¹, c, in connection
with the contact-pieces s* and s² of the bell-push respectively, substantially as
described.
Dated this 15th day of May 1894.
J. G. LORRAIN,
Associate Agent.