IMPROVEMENTS IN TELEPHONE SWITCHES AND CIRCUITS
Year: 1884

page_text: "
I PETER JENSEN of 33 Chancery Lane in the County of Middlesex, Fellow of
the Institute of Patent Agents do hereby declare the nature of said invention for
"IMPROVEMENTS IN TELEPHONE SWITCHES AND CIRCUITS A communication to
me from abroad by Messieurs Stockholms, Bell Telefon Aktiebolag, Stockholm
Sweden; to be as follows:-
This invention is intended for fitting two telephones (A and B) in different
neighbouring houses or in different parts of the same house at one end of a single
line, the other end of which is in direct connection with the central exchange
station in such way, by means of a switch actuated from the central station, that
the holder of either of the two telephones (A or B) will be able to communicate
without hindrance with any subscriber, without the other holder (B or A) being
troubled nor able to interrupt the communication.
When A for instance has ceased to talk, B can use the line in the same way.
The exchange is made automatically and so to speak without the subscribers
knowing.
The central exchange, in order to connect any other subscriber with either of the
two (A or B) has only to send forth during a moment, a positive or negative current,
depending upon which of the two (A or B) is wanted, whereby the circuit is switched"
to one side or the other and connection is made as required to A. or to B.
The two holders (A and B) can also use the mutual line for talking to each
other.

page_text: COMPLETE SPECIFICATION.
"
I, PETER JENSEN of 33 Chancery Lane in the County of Middlesex Fellow of
the Institute of Patent Agents do hereby declare the nature of said Invention for
"IMPROVEMENTS IN TELEPHONE SWITCHES AND CIRCUITS (A Communication to
me from abroad by Messieurs Stockholm's Bell-Telefon-Aktiebolag, Stockholm,
Sweden) and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This Invention is intended for fitting two telephones A and B in different
neighbouring houses or in different parts of the same house at one end of a single
line, the other end of which is in direct connection with the Central Exchange
Station in such a way, by means of a switch actuated from the central station that
the holder of either of the two telephones, A or B shall be able to communicate
without any hindrance with any subscriber, without the other holder B or A being
troubled nor able to interrupt the communication and so that the two holders A
and B shall also be able to use the mutual line for talking to each other.
When
▲ for instance has ceased to talk, B may use the line in the same way. The
exchange is made automatically and so to say without the subscribers knowing it.
Figure 1 of the accompanying drawings is a diagram showing the two telephones
for A and B with the switch appliance, and with the circuits for connecting with
the central station, main line, and local batteries. Figure 2 is a part sectional
elevation and Figure 3 a plan of the switch appliance. Lis the line leading to
the Central Exchange and terminating in the contact point H against which the
spring presses, thus through the contact f and bobbins E and D and the line L'
connecting the latter with the switch appliance and its lever armature C which at
its upper end has two small springs making contact with the screw a or the screw b.
The latter through wires A' and B' connect with instruments A and B and thence
to earth in the usual manner.
A and B are connected with the switch through A¹ and B' which circuits
traverse the bobbins D¹ and E' and are finally united into a single line which is
connected with one pole of a local battery, the other pole of which is connected to
earth.
The central exchange in order to connect any other subscriber with either of the
two, A or B has only to send forth during a moment, a positive or negative
current, depending upon which of the two A or B is wanted, whereby the
armature C is drawn to one side or the other by the electromagnets D or E and
the circuit switched to one side or the other and connection is made as required to
A or B by reason of the polarized armature contact C being thereby automatically
shifted over against the contact a or b thus connecting the line L through either A³
or B with the instruments A or B.
The lines A and B' are connected with the bells at A and B. A small spring
near the telephone hook which forms the terminal of A¹ and B' makes contact with
the hook and to earth every time the receiver is lifted off, thus closing the circuit of
the local battery through the bobbin D¹ or E¹ to the earth. The armature there-
fore makes contact with a or b according to whether A or B takes off the receiver

page_text: and consequently A or B can connect himself automatically into the central office
line. The contact F is provided with a button F1 which may be arranged on the
wall or back board of the instrument or be put inside the call bell with only the
end protruding. If A desires to speak to B he depresses the button or key F',
thus making contact with G, rings up B and holds the button in the depressed
position during the whole conversation. Whilst A and B are thus speaking with
each other, the central station line remains open, thus preventing any interference
and showing the latter that A and B are talking together. If B in the first
instance desired to speak with A, he calls up the Central Station in the usual
manner asks for A, replaces his receiver on the hook and awaits the signal from A.
The Central Exchange calls up A and tells him to ring up B and A then depresses
the button F¹ and can thus talk with B.
Having now particularly described and ascertained the nature of said Invention
and in what manner the same is to be performed I declare that what I claim as
the invention communicated to me is
The automatic telephone switch or arrangement and combination of circuits and
switch appliances substantially in the manner described and shewn for the purpose
of enabling either of two subscribers of a telephone exchange or system having
their telephones fitted in different neighbouring houses or in different parts of the
same house and connected to one and the same end of a single line leading to the
Central Exchange to communicate unhinderedly with any other subscriber and also
with the other aforesaid subscriber.