Improvements in Telephonic Switch Boards.
Year: 1889

page_text: Date of Application, 1st June, 1889
Complete Specification Left, 1st Mar., 1890-Accepted, 19th Apr.,
1890
PROVISIONAL SPECIFICATION.
Improvements in Telephonic Switch Boards.
We, HUBERT FEILDEN JACKSON of Queen Victoria Street, in the County of
Middlesex, Gentleman, and DANIEL SINCLAIR of Royal Exchange Buildings, in the
City of Glasgow, Electrical Engineer, do hereby declare the nature of, this Invention
to be as follows:-
In telephonic exchanges working what is known as the "Multiple System" the
switch boards are formed in sections provided usually with two hundred lines from
subscribers whose calls are attended to by the operators for the sections but each
containing line jacks or switches for all the subscribers connected to the whole of the
sections or boards so that every subscriber may be called from any one section. Thus
an exchange of one thousand subscribers is provided with five boards or sections
having each two hundred indicators with subscriber's lines terminating at the table
and one thousand line jacks on each board by means of which any of the subscribers
connected to the section may be connected to the remaining subscribers, five thousand
line jacks in all being necessary. .In an exchange of five thousand subscribers twenty-
five boards or sections are required with five thousand line jacks in each or in all one
hundred and twenty-five thousand line jacks.
Our invention which is a development of the improvements in telephonic apparatus
described in the Specification filed with an application for Patent No. 859 of 1889,
has for its object to permit of one half of the line jacks being dispensed with in
working telephonic exchanges on the multiple switch board system.
To that end in lieu of a switch board having the portion which carries the line
jacks placed in a vertical position over a single switch table carrying the usual
indicators, cords, switches and other accessories used by the operators in calling and
making connections between subscribers we form a duplex switch board in which the
part carrying the line jacks is laid horizontally between switch tables on two opposite
sides and each provided with indicators, cords and other usual accessories so that
operators placed at both switch tables may use the same board to make connections to
all the subscribers from any of the two different sets of subscribers whose calls they
attend.
We may also employ with the arrangements above described the improved switches
and other accessories described in the Specification above referred to as adapted for
use with duplex switch boards and in some cases more especially when the usual
arrangements of cords are not available in converting existing switch boards into
duplex boards of the kind hereinbefore described we suspend the connecting cords
and plugs from a framing situated over the board or table in order to lessen friction
and consequent wear of the cords and to facilitate the operation of inserting the plugs
into the jacks.
1000
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in Telephonic Switch Boards.
We, HUBERT FRILDEN JACKSON Gentleman and DANIEL SINCLAIR, Electrical
Engineer, both of Oxford Court, Cannon Street, in the City of London, 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 exchanges working what is known as the "Multiple System" the

page_text: switch boards are formed in sections provided usually with two hundred lines from
subscribers whose calls are attended to by the operators for the section but each
containing line jacks or switches for all the subscribers connected to the whole of the
sections or boards so that every subscriber may be called from any one section. Thus
an exchange of one thousand subscribers is provided with five boards or sections
having each two hundred indicators with subscribers' lines terminating at the table
and one thousand line jacks in all being necessary at each table. In an exchange of
five thousand subscribers twenty five boards or sections are required with five
thousand line jacks in each or in all one hundred and twenty five thousand line
jacks.
Our Invention which is a development of the improvements in telephonic apparatus
described in the Specification of Letters Patent Number 859 of 1889, has for its object
the reduction of the number of line jacks required at the switch tables, practically
one half of the line jacks being dispensed with in working telephonic exchanges on
the multiple switch board systein in accordance with our invention.
To that end in lieu of a switch board having the portion which carries the line
jacks placed in a vertical position over a single switch table carrying the usual
indicators, cords, switches and other accessories used by the operators in calling and
making connections between subscribers, we form a duplex switch board in which the
part carrying the line jacks is laid horizontally between switch tables on two opposite
sides and each provided with indicators, cords and other usual accessories so that
operators placed at both sides of the switch table may use the same set of line jacks
to make connections to all the subscribers from any of the two different sets of
subscribers whose calls they attend. We also in general suspend the connecting cords
and plugs from a framing situated over the board or table instead of fitting them on
the switch table in order to lessen friction and consequent wear of the cords and to
facilitate the operation of inserting the plugs into the jacks, and we employ by
preference what is known as the single cord system in which one cord and plug is
provided for terminating each subscriber's line and which is adapted to work either
direct single lines or return circuit lines. The invention is also applicable to small
boards not worked on the multiple system.
In the accompanying drawings figure 1 sheet 1 is a transverse vertical section,
figure 2 a front elevation and figure 3 a horizontal section on the line X-X figure 2
showing our improved duplex switch board as fitted to operate with the ordinary
double cord arrangements for connecting subscribers' lines. The connections used
in this board are diagramatically represented in figure 4 sheet 2. Figures 5, 6, 7
and 8 are similar views representing our improved duplex switch board and con-
nections for operating on the single cord system.
The board A in each case is laid horizontally instead of as hitherto being vertical
and the jacks are placed in rectangular spaces a, as shown at figures 3 and 7 one
hundred line jacks being fitted in each space the jacks being placed vertically in the
board and all within reach of operators on both sides whilst the numbers by which the
jacks are indicated are formed on inclined surfaces as indicated on an enlarged scale
at figures 9 and 10 so as to be visible from both sides of the board. The cords and
plugs B, B, for connecting the subscribers through the jacks are in the double cord.
system represented at figures 1 to 4 for convenience of working suspended one
half from above and the other half carried upon the shelf C of the table as shown.
The upper cords and plugs are used for connecting on the line jacks on the flat portion
of the board A to any subscriber's wire whilst the lower cords and plugs are used
for connecting to the local jacks which are placed horizontally at D in the vertical
faces of the switch board. This arrangement avoids confusion of the cords when
a large number of connections are made simultaneously.
In the single cord system as represented in figures 5 to 8 and in which a single
cord with plug B₁ is used to terminate each subscriber's line the whole of the cords
are by preference suspended from a framing above the board A, and for convenience
the plugs rest on earth connections at E arranged in successive stepped rows so that
the numbers of the plugs in the several rows may be clearly seen and so as to enable

page_text: the operator to readily select the plug desired for use. In this case no local jacks
are required. The indicators F are in both the double and single cord arrangements
placed on the vertical faces of the board on both sides and the switches on the shelf C
a switch being provided for each line. The switches may however be dispensed with
and the subscribers rung from an operator's set which is common to all the lines on
the board. In the case of return circuit wires a special plug having its parts
insulated and a twofold cord is substituted for the usual earth connection.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner. the same is to be performed we declare that what we
claim is:-
1. A duplex telephonic switch board constructed and furnished for operating with
double cords and plugs substantially as hereinbefore described.
2. A duplex telephonic switch board constructed and furnished for operating with
a single cord and plug for each subscriber substantially as described.
3. A telephonic switch board having a horizontal table carrying the jacks and
arranged to permit of operators working from both sides of the board substantially as
described.
4. A telephonic switch board having a horizontal table carrying the jacks and
having the cords and plugs for connecting subscribers suspended thereover substantially
as described.
Dated this Twenty-eighth day of February 1890.
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.