Improvements in Telephone Switchboards.
Year: 1891

page_text: Date of Application, 21st Oct, 1891
Complete Specification Left, 21st July, 1892-Accepted. 27th Aug.. 1892
PROVISIONAL SPECIFICATION.
Improvements in Telephone Switchboards.
I, ALFRED WHALLEY, of Helsby (near Warrington) in the County of
Cheshire, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
This is an improvement in multiple metallic-circuit switchboards described in my
Specification Patent No. 3276, 1890 for controlling wires with which an "earth"
connection is made at subscribers' stations when disengaged.
My object is to avoid the expense of providing a separate "earth" connection at
each subscriber's station and to substitute a common "earth" connection at the
exchange to which each pair of wires is joined so long as they remain free for a
connection for conversation.
Each subscriber's two wires are as usual connected to a jack in each section of
the board, the last jack being joined to an annunciator. In that pattern of board
in which two plugs, joined by a flexible cord, are used for connecting two
subscribers' wires, each subscriber's annunciator is joined permanently to the
common "earth" and is cut out of the circuit when a plug is inserted in any jack
belonging to the same subscriber. In the single-cord pattern of switchboard,
having a separate plug permanently connected to each subscriber's wires, each
annunciator is joined to the common "earth" by means of a split socket in which
the plug belonging to the same wires normally rests, but in such a way that the
removal of the plug from the socket breaks the connection of the annunciator with
the "earth." The insertion of a plug in any jack breaks the connection of the
jack with the annunciator belonging to the same wires.
To make the "engaged" test possible the frames or front-sockets of all the jacks
belonging to a subscriber are connected together by a separate wire. The frame
of the first jack, that at which the subscriber's wires enter the board, is connected
permanently to its longest spring. This same spring normally touches a contact-
spring which is connected to the longest spring of the next jack, and so on until
the longest spring of the last jack is reached. This normally touches a contact-
spring connected to the annunciator and to earth normally. The frames of all the
acks, except the first, are insulated from their springs.
When an operator tests at the frame or front socket of any jack belonging to
disengaged subscriber the complete circuit to "earth" from the operator's
esting plug is thus through the jack-frames up to the first jack, then back
hrough the springs of all the jacks to the last jack and thence to "earth"-but
f a plug is fixed in any jack, separating its longest spring from the contact-spring,
here is not a complete circuit to "earth" and a test at any other jack belonging to
he same wires reveals to the operator that the subscriber is engaged.
Dated this 20th da
001
ALFRED WHALLEY.
COMPLETE SPECIFICATION.
Improvements in Telephone Switchboards.
I, ALFRED WHALLEY of Mount View Helsby (near Warrington) in the County
of Cheshire, Electrical Engineer 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 :-
This is an improvement in multiple metallic-circuit switchboards described in my
Specification Patent No. 3276, 1890 and has for its object the substitution of a
Price 1

page_text: common "earth," or its equivalent for testing purposes, at the exchange for the
separate earth connections needed at each subscriber's station.
Each subscriber's two wires are as usual connected to a jack in each section of the
board, the last jack being joined to an "annunciator. In the single cord pattern of
switchboard having a separate plug permanently connected to each subscriber's
wires, each annunciator is joined to "earth" by means of a split socket in which
the plug belonging to the same wires normally rests but in such a way that the
removal of the plug from the socket breaks the connection of the annunciator with
the "earth." The insertion of a plug in any jack breaks the connection of the jack
with the annunciator belonging to the same wires.
Figure 1 shows one subscriber's set of apparatus on a single cord "multiple
--switchboard-under this-improvement. A B are the incoming line wires. JJJ
and J, are jacks in different sections of the board of which is the answering jack.
This has its two longer springs connected through the other jacks to the line
wires A, B, and also to the subscriber's double plug P; the two shorter springs are
joined to the subscriber's annunciator I. One side of this annunciator is also joined
to one half S₁ of the split socket in which plug P normally rests. The other
half S, of the split socket is joined either to "earth" or to the common test
battery Z Figure 2. The line wire A is further permanently connected to the front.
socket of jack J, by means of its bolt & thence by means of wire C to the front
sockets of all the other jacks which are insulated from their springs. The bars of
the plug P carries an an insulated metal ring R which makes contact between 'the
two halves of the split socket. By means of the connections shown in Figure 1, the
"earth" is removed from the subscriber's line either if the plug P is lifted out of
the socket or if any other plug is inserted in one of the jacks; and at all times the
front sockets of all the jacks are available for tests. Also if the operator inserts
her plug in the answering jack, the subscriber's annunciator & its "earth "con-
nection are cut off but the plug P remains connected to the circuit and can be used
by the operator while receiving a call, first as a test plug and then to 'form
connection with the required subscriber's line. The removal of the operator's plug
from the answering jack restores the annunciator to the circuit, but without the
" earth connection if the plug P is out of the socket. One method of arranging
the operator's combined testing & speaking circuit for a single cord multiple board
is shown in Figure 2 where O is the operator's plug, T the telephone receiver
and Q the induction coil shewing only its secondary circuit. One point of the
operator's circuit, preferably where the resistance and self-induction measured to
the plug each way make a balance, is joined to a test battery Z which is connected
to "earth." It is evident, however, that connection with the earth is not necessary
for the purpose of the tests; if we connect all the operators' circuits to one common
test battery and one half of all the subscribers' split sockets to the same battery we
avoid connection with the earth and also make it impossible for any operator's plug
when in any jack to cause a false "test" from the test battery.
"
"
Figure 3 shows a subscriber's set of apparatus for a double cord' multiple board
in which cach line is provided with an annunciator only two independent plugs
and cords being used by the operator to connect two subscribers. The jacks and
annunciator are connected as in Figure 1, except that one side of the annunciator
is joined permanently to "earth or its equivalent. The two plugs used for a
connection will be connected to the operator's testing & speaking circuit like the
single plug in Figure 2the second plug being connected at points m, n, therein.
The operator's telephone & induction coil are replaced by a ring off annunciator
when the plugs are left connecting two subscribers' for conversation, but it is not
necessary to shew this, nor the switching apparatus employed.
Having now 'particularly described & 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 pistollis hirouit miiltiple Switabhoands in which ach nair of wires is

page_text: provided with a jack in each section of the board and also with an annunciator, a
double-circuit plug and a split socket, the construction of the circuits and mechanism
in such manner that the fronts of all the jacks are permanently connected to one of
the line wires; that when the plug rests in the split socket the same line wire is
connected to "earth" or to its equivalent for testing purposes, which connection is
broken either if the plug is removed from the split socket or if another plug
is inserted in one of the jacks; that the line wires are normally connected to the
annunciator, which connection is entirely broken if a plug is inserted in any of the
jacks and also that when the operator's plug is inserted in the "answering "jack,
the double-circuit plug belonging to the same wires can be used both for testing for
the "earth connection on any other jack on the board and for completing a
connection for conversation.
"
2. The combination with each pair of wires of a metallic-circuit multiple switch-
board of a switch jack in each section of the board-each jack having four insulated
springs and an insulated frame or front socket-and an annunciator, a double circuit
plug and a split socket connected as illustrated by Figure 1 and as described.
3. In metallic-circuit multiple switchboards in which each pair of wires is'
provided with a jack in each section of the board, and also with an annunciator the
construction of the circuits and mechanism in such manner that the fronts of all the
jacks are permanently connected to one of the line wires; that the same line wire
is normally connected to "earth or its equivalent for testing purposes, and that
both line wires are normally connected to the annunciator, both of which normal
connections are entirely broken if a plug is inserted in one of the jacks.
"
4. The combination with each pair of wires of a metallic-circuit multiple switch-
board of a switch-jack in each section of the board--each jack having four insulated
springs and an insulated frame or front-socket-and an annunciator connected as
illustrated by Figure 3 and as described.
5. The combination in a metallic-circuit multiple switchboard of a common
testing battery joined on one side to the testing and speaking sets of all the
operators and on the other side joined to the front parts of the jacks of all non-
speaking subscribers, through one of each pair of line wires and the normal
connection provided with the equivalent to earth for testing purposes-each
operator's testing and speaking set comprising a telephone receiver, an induction
coil, microphone transmitter and speaking battery and one or two plugs-direct
connection with the "earth" being avoided.
Dated this 20th day of July 1892
ALFRED WHALLEY.