IMPROVEMENTS IN TELEPHONE- EXCHANGE APPARATUS AND SYSTEMS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Ernest de Pass at the Offico
of the Commissioners of Patents on the 27th September 1881. A communi-
cation from abroad by Frank Shaw, of the City and State of New York, and
William A. Childs, of Englewood, New Jersey, both in the United States of
America,
ERNEST DE PASS, of the Office for British and Foreign Patents, 68, Fleet
Street, in the City of London, Patent Agent. "IMPROVEMENTS IN TELEPHONE-
EXCHANGE APPARATUS AND SYSTEMS." A communication from abroad by Frank
Shaw, of the City and State of New York, and William A. Childs, of Englewood,
New Jersey, both in the United States of America.
This Invention relates to improvements in telephone switch boards or tables and
other necessary apparatus for receiving orders for connections and disconnections
from subscribers, and for giving and receiving orders for trunk-line connections and
disconnections, and also for making such connections and disconnections, the
former being made between subscribers' wires of one group or central office, and
the latter between the subscribers' wires of any two groups or central offices
through trunk lines for subscribers' use between such central offices.
The objects of this Invention are to economize space and expense by reducing
the size of the switch board, to save in the number and expense of operators, to
save confusion, delay, repetition, and errors, and secure quietness, promptness, and
accuracy, and at the same time to put the whole switch board under the control of
such operators, one or more.
In one system now in use a long and high continuous switch board is employed,
say sixty feet long and six feet high, for less than 1000 wires and subscribers
before which the operators rush back and forth in more or less confusion to perform
their duties. In another system desks having about fifty wires and apparatus for
connection are provided for each operator and increased as the subscribers increase.
Both these systems are objectionable for evident reasons.
In this Invention the apparatus is arranged in the form of a table, around which
the operators may sit, having the whole top of the table within the reach of each
operator, one or more. On the top part of such a table is a case containing, say,
four hundred small metallic tubes standing closely together like so many candle
moulds in a frame. This case is made as follows:-At top and bottom it has n
board or plank, say thirty two inches long, eight inches wide, and two inches thick,
perforated with four hundred holes, say seven sixteenths of an inch in diameter.
These holes are disposed in four sections, each having ten holes on a side, making

page_text: one hundred holes in a section, four hundred in all, and three quarters of an inch
from centre to centre. These holes receive tubes which are twentysix inches long
and extend between the two boards or planks, and say half way through the same
at the ends. Each hole in the bottom plank has the end of a subscriber's wire
inserted therein. This wiro is secured by simply driving the lower end of the tube
into the hole, the result of which is that each tube becomes practically an
extension of the particular subscriber's wire inserted in that particular hole. The
bottom holes are made preferably of the same size as the bottom ends of the tubes,
so as to drive solidly and hold the subscriber's wire firmly, and at the same time
make and maintain electrical contact. The top holes are made of such a size as to
allow the tubes to pass easily from above and through them into the lower holes
The boards may be made from two or more layers or pieces of wood secured
together in any usual way. Plates of metal provided with holes are made
continuous with those in the top board. These plates are ground plates, having
ground connections, and they may be made in sub sections if convenience requires.
These plates rest upon the top board with sufficient space between their under
sides and the upper ends of the tubos to insure insulation therefrom.
Rods and flexible conducting cords with plugs or equivalent contrivances termi-
nating the same are provided. These rods are cut away at top to receive flexible
flat springs, preferably made of German silver. These rods being dropped into the
tubes from above will fall by their own weight within the same, drawing the cords
after them, until the broad part of the plug rests upon the ground plate to which
the tube belongs. The springs are so attached to the rods as to project. beyond
their surface and press with sufficient force against the inside of the tubes to effect
electrical contact, consequently-when-a-plug rests upon a plate a ground connection
-is-established from the subscriber's wire. Each one of the four hundred tubes has
its rod, cord, and plug, and every one of the four hundred wires-being-so-connected
atmospheric electricity will be conducted to the ground safely, and all the other
advantages incident to a normal ground connection will be secured. Signalling
plates placed on each side of the ground plates are battery plates. A third set of
plates is also provided and serves as battery plates. The ground plates are also
battery plates, and have circuit breakers or pole changers in their circuits. The
signalling plates bear numbers 1, 2, 3, &c., which are used to number each row of
holes in the first named plates for the guidance of the operators. Connecting bars or
plates are provided with holes and receive the plugs for the purpose of connecting
any two wires. Most of these last are used to connect subscribers' wires of the
same group or table; but when there are two or more groups or tables in the same
or different offices connected by trunk lines, a sufficient number of these bars, say
Nos. 1, 2, and 3, is reserved, and is connected with corresponding bars on other
tables by trunk lines in a manner and for purposes to be described hereinafter. Or,
if preferred, the trunk lines can be connected with the tubes in the same manner
as subscribers' wires, when connections can be made as desired in the regular way
through the connecting bars or plates. Each one of these bars or plates is provided
with a key which, on being depressed, makes contact with the battery strip or
plate for the purpose of ringing the bell of a subscriber in case he does not answer
promptly after he has been connected and without disconnecting for that purpose.
Transmitters are provided and are located conveniently at each corner of the table,
say, one for each operator. The number of connection plates or bars used is thirty
five on each sido for the connections of four hundred subscribers. This number
may be increased as required by increasing calls for connections by making them
narrower, placing them nearer together, or cutting them up into sections. The
operators are supposed to have for convenience a receiving instrument secured to
the head and ear so as to leave both hands free to manipulate the apparatus. The
switch table may be operated upon several systems, the one preferred boing that
known as the Law system, and described in the United States Letters Patent
granted to the within named Frank Shaw, No. 220,874, and dated October 21st,
1879.

page_text: The method of operation will then be as follows:-The operator receiving the
order, say, to connect 121 with 221 by the signal wire and receiving instrument in
its circuit, will take the plug of 121 in one hand and the plug of 221 in the other
hand, and ring the bell of each by touching the plugs to the nearest battery plate
of the second set. He will then connect those subscribers' lines 121-221 by
inserting both plugs into any one of the connecting bars or plates reserved for local
connections and not in use. When the order to disconnect is received from either
121 or 221, the operator removes the plugs from these connecting bars or plates,
and giving each a touch to one of the signalling plates sends signals, one to each
party, over their private wires that their lines are disconnected. Each receiving
instrument having a different set of subscribers' officers on the signal wire with
which it is connected, it may be that the order to disconnect may not come to the
operator who made the connection, since the party first called for and not the
calling party may give the disconnect order, but may come to either of the other
operators sitting around the table, or rather will come to the operator on whose
signal wire the subscriber giving the order is located. On receiving this order,
either of the operators being able to reach the entire table can readily execute the
order. Both the connections and the disconnections are made in silence, and in
obedience to orders received at the ear of the one operator, and without the
knowledge of the others.
Switches substantially like those described and shown in the United States
Letters Patent of the within named Frank Shaw previously referred to are
employed.
Three of these switches keep the several receiving instruments in circuit with
signal wires. But in case an order comes for connection with a subscriber's wire of
another group or office, provision having been made therefor, the proceduro is as
follows: Inserting the plug of, say 121, after the signal as described, into one of
the connection bars or plates reserved for trunk line connections, say No. 1, 2, or 3,
the operator puts his finger on the button of his switch and pressing the same
thereby switches his instrument into the circuit which connects with the group to
which the desired number belongs, and requests the operator thero to connect 621
with No. 1 by saying, "Connect 621 with 1," which being done after the usual
signal to 621, the two subscribers will be found in connection through the trunk
line which connects the trunk line bars No. 1 for conversation. The order to
disconnect may be sent in the usual manner through the operator first called by
121, and through him to the operator who received the order to connect 621 with
No 1; or if this order comes from 621 to any operator at the group or table to
which 621 belongs, the status is evident at a glance, and the order is sent to the
group or table to which 121 belongs through the operator on the trunk signal wire
and executed in the usual way (according to the group from which the order
emanates). The line, which beginning at the ground passes into the switch near
the operator of the upper side of the group No. 1 or table, also passes into the
switches near the other two operators and also the operator of the same group. It'
will be observed that it enters and passes out at the bottom part of each one of
these switches, but on reading the switch of the group No. 2 near the operator of
that group, enters that switch and emerges to ground at its top. This arrangement
enables any one of the three operators of group No. 1 to signal and communicate
with the operator of group No. 2 by simply depressing his switch-button and
throwing his instruments into the circuit, and this without disturbing either the
two other operators or the operator of group No. 1. The line of group No. 2
connects the switches and operator of that group with the operator of group No. 1
in a similar manner. The operators of both groups receive and execute the trunk
line connection and disconnection orders of the other group. The table top is
about thirty two inches square, and can be reached at all points by any one of
four operators sitting around it. When the number of wires centering in one
group is too large for one table we provide another table of a similar construction
connected by trunk lines. And whether these additional groups or tables are in

page_text: the same room or office, or located at a distance, the connecting apparatus between
them is the same and so likewise is the method of operation.
The weighted rods are solid, and operate by their weight so as to drop within the
tubes automatically when the plugs or their equivalents are withdrawn from
their connecting bars or plates and released, the broad part of the plugs being
drawn thereby on to the ground plates, thus maintaining a normal ground
connection when the several lines are not in use for conversation between
subscribers. But in whatever position the rod may be, the electrical circuit
connection with the tube and its line is always complete through the German-silver
spring. Continuous contact may be effected by any other usual means for securing
proper rubbing pressure between the rod and the tube, but the light spring
described is most satisfactory. A rubber strip, or a spiral or other spring may be
used instead of the weighted rods to draw the contact springs and the flexible
cords automatically into the tubes with the plug bearing upon the ground plate as
described. The tubes and rods may be placed horizontally instead of upright, and
still be made to operate and effect very great economy of space, especially where
the number of connections may not be so great as to require more than one
operator.
It is evident that the relations between the tubes and the rods may be reversed.
The rods will then be stationary and in contact with the subscribers' wires in the
bottom board or plank, and the tube will be movable, attached to the flexible cord,
and capable of performing the functions of the rods in a similar manner.. Or one
or more rings may be substituted for the tubes moving up and down on-the-rods
under-the-control-of-weights.or. of springs. Or any other usual form of guide may
be substituted to control the movement of the circuit maintaining springs or other
devices. The substitution of a permanent connection is also contemplated-between
each subscriber's wire in the bottom board or plank and the flexible cord by means
of a spiral spring attached in any usual manner to each. The spiral spring would
then act both as a spring to automatically withdraw the cord and plug, and also as
part of the circuit. These springs may be made movable in tubes made of wood
or other suitable material, or held and kept separate from the adjoining springs by
any usual kind of guides.
This system of numbering the subscribers' wires and plugs is as follows:-Each
one of the four plates contains one hundred plugs. That to the left contains the
one hundreds, the next to the right the two hundreds, the next the three hundreds,
and the next the four hundreds. Each hundred being thus grouped, any number
can be found instantly. Each one of these subgroups or sections has on each of
their four sides numbers, as shewn from 0 to 9, opposite cach row of ten holes.
Consequently the eye and hand of the operator instantly recognizes the location
of the plug of any subscriber and subscriber's wire, and he may therefore make
the connections and disconnections instantly, since the operators sitting upon either
side of the table can easily follow the decimal arrangement of the plugs between
one and one hundred in each section.