Improvements in Telephonic Switching Apparatus.
Year: 1886

page_text: Date of Application, 9th June, 1886.
Complete Left, 9th Mar., 1887.
Complete Accepted, 15th Apr., 1887.
PROVISIONAL SPECIFICATION.
Improvements in Telephonic Switching Apparatus.
We, ALFRED ROSLING BENNETT, of 90A George Street, Edinburgh, in the County
of Mid Lothian, and CHARLES GEORGE WRIGHT,. of 34 Saint Andrew Square,
Edinburgh, aforesaid, Telegraph Engineers, do hereby declare the nature of this
invention to be as follows:-
In telephonic switching systems which comprise the use of indicators reserved for
the purpose of enabling subscribers to signal to the switching operator the termination
of a communication, such indicators being commonly known as "ring-off indicators"
or "ring-off drops," we connect a branch from the coils of each indicator to its
shutter or drop, and provide a contact, upon which the drop or shutter rests when
it falls, which contact is in communication, either directly or through a switch
or key with the operator's speaking instrument.
By this means a subscriber can obtain instant speaking communication with
the operator either during or immediately after a conversation with another subscriber,
inasmuch as the moment he causes his ring-off indicator to fall he is in communication
through its shutter and contact with the operator.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow,
Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Telephonic Switching Apparatus.
We, ALFRED ROSLING BENNETT of 90A George Street, Edinburgh, in the County
of Mid-Lothian and CHARLES GEORGE WRIGHT of 34 Saint Andrew Square
Edinburgh, aforesaid, Telegraph Engineers 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 telephonic switching systems which comprise the use of indicators reserved
for the purpose of enabling subscribers to signal to the switching operator the
termination of a communication, such indicators being commonly known as "ring-off"
indicators or "ring-off" drops, we connect a branch from the coils of each indicator
to its shutter or drop, and provide a contact, upon which the shutter or drop rests
when it falls, which contact is in communication, either directly or through a switch
or key, with the operator's speaking instrument.
By this means a subscriber can obtain instant speaking communication with
the operator either during or immediately after a conversation with another subscriber
inasmuch as the moment he causes his ring-off indicator to fall he is in communication
through its shutter and contact with the operator.
The invention may likewise be advantageously applied to the indicators provided
in connection with each subscriber's line for the purpose of calling the operator's
attention before a conversation has been commenced. In this case the subscriber
is put into speaking communication with the operator as soon as he causes his drop
to fall, and the operator is relieved of the necessity of inserting a plug or of making
any corresponding movement for the purpose of placing the speaking instrument
in connection with the subscriber's line.
On the accompanying drawings figs. 1 to 4 show various methods of connecting
the subscribers' lines to the indicators in order to attain the results aimed at by the
invention. In figure 1, R, is a resistance composed of any suitable substance,
interposed in the earth wire for the purpose of compelling a portion of the current
to traverse the speaking instrument T when the shutter S has fallen upon the
contact C.
It is not necessary that the operator's speaking instrument be connected directly
to the contact C. A condenser or a phonophore may be interposed between them,
the contact C, being connected to one plate of the condenser or to one wire of
the phonophore while the speaking instrument T is connected to the other plate
of the condenser or to the other wire of the phonophore. When the connections

page_text: are made as in figuro 4, the condenser or phonophore is interposed between the
shutter S, and the speaking instrument T.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we delare that what we claim is:
1. The improvements in telephonic switching apparatus substantially as herein
described.
2. In telephonic switching apparatus the employment in conjunction with each
indicator or drop of a contact piece and connections substantially as described
to provide for direct communication between each subscriber and the exchange
operators telephone upon the falling of the subscriber's indicator or drop.
Dated this Eighth day of March 1887.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow,
Agents.