Improvements in and relating to the Counting and Recording of the Number of Messages Transmitted over Telephonic or other Signalling Circuits.
Year: 1897

page_text: Improvements in and relating to the Counting and Recording of
the Number of Messages Transmitted over Telephonic or other
Signalling Circuits.
We, DANIEL SINCLAIR, the Engineer-in-Chief to The National Telephone Com-
pany, Limited, of Oxford Court, Cannon Street, in the City of London, and
WILLIAM JAMES GRAY, a District Engineer to The National Telephone Company,
at Swan Arcade, Bradford, in the County of Yorkshire, do hereby declare the
nature of this invention to be as follows:-
The object of our invention is to provide an efficient automatic system for
recording the actual number of calls, and the duration of same, on a telephonic,
telegraphic, or other signalling circuit.
Heretofore, in order to obtain a record of the amount of work passing over such
a signalling circuit, it has been necessary to employ an operator to note down
the various calls, this method being cumbersome, and, necessarily, inaccurate.
Our invention is specially applicable to telephonic systems, in order that data
may be obtained to regulate the number of operators required to properly cope
with the exchange work, and the assignment of the requisite number of trunk
or junction lines to other towns.
The apparatus necessary would be situated at the central station. This con-
sists, broadly, of a roll of chemically prepared paper, drawn over a brass drum,
or plate, by means of suitable clock-work so geared as to cause the paper to travel
at the rate of, say, three inches per hour. Pressing on the paper, exactly over
the brass drum, or plate, is a number of light metal springs, or studs, so set as to
keep an even pressure on the paper, these being in connexion with the test or line
circuits, as hereinafter explained.
In order to apply our invention to a multiple telephonic switch-board, the line,
commonly known as the test-wire, must be extended, and connected to a spring,
or pointer, which lightly presses on a slip of paper, saturated with a chemical
solution, (such as iodide of potassium and starch, or ferrocyanide of potash, or
any chemical solution which will decompose under the influence of an electric
current), the paper slip being carried forward at a predetermined rate.
As soon
as the operator at the exchange inserts a plug into a subscriber's jack, a current
is put on the test-wire, which not only serves as a signal to the other operators
that the line is in use, but also decomposes the chemical on the paper slip, thus
automatically recording the exact moment at which the plug was inserted, and
continuing to record until the plug is withdrawn.

page_text: 66
Our invention may also be used on boards where what are commonly known as
make-and-break jacks" are in use. Under such circumstances, we would prefer-
that the method of recording the calls, as described, be reversed, that is to say,
that so long as the line of the subscriber is disengaged, the current shall flow
over the recording spring, and mark on the prepared paper, but, as soon as the
plug is inserted in the jack, such marking shall cease. In this modification, the
connexions must be slightly altered, and, instead of the test-wire being extended,
the connexion is taken from the centre-point of the line indicator to the recording
spring, the battery being placed between the earth and the drum, or plate, over
which the prepared paper travels. It is also necessary, in this case, to earth the
centre-point of the bell at the sub-station.
Our invention may be further adapted to single-cord boards by so arranging the
connexions at the plug socket that, on the removal of the plug from its seat, the
earth shall be taken off the pointer, so that the record will cease until the plug
is again returned to the socket.
Our invention may still further be adapted to night-watchmen's tell-tale
systems, by replacing the clock, as heretofore used, by an electrical switch, which
shall close the circuit for a prearranged period, thus indicating on recording:
apparatus, provided for that purpose, the time of the watchman's visit. It can
also be used by railway companies for recording the number of times the points,
or signals, are moved, likewise, the length of time they remain in any position
on any particular line of rails.
Dated this 16th day of June 1897
DANIEL SINCLAIR.
WILLIAM JAMES GRAY.
Improvements in and relating to the Counting and Recording of
the Number of Messages Transmitted over Telephonic or other
Signalling Circuits.
We, DANIEL SINCLAIR, the Engineer-in-Chief to The National Telephone Com-
pany Limited, of Oxford Court, Cannon Street, in the City of London, and
WILLIAM JAMES GRAY, a District Engineer to The National Telephone Company,
at Swan Arcade, Bradford, in the County of Yorkshire, 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: —
Heretofore, in order to obtain a record of the amount of work passing over a
signalling circuit, it has been necessary to employ an operator to note down the
various calls or signals, this method being, however, cumbersome and inaccurate.
Our invention is specially applicable to telephonic systems, in order that data
may be obtained for regulating the number of operators required to properly cope
with the exchange work, and for assigning the requisite number of trunk or
junction lines to other towns.
In applying our invention to a telephonic system the apparatus necessary would
be situated at the central station. This consists usually of a roll of chemically
prepared paper, drawn over a metal drum, or plate, by means of suitable clock-
work, so geared as to cause the paper to travel at the uniform rate of, say three
inches per hour, and a number of light metal springs or studs pressing on the
paper, exactly over the metal drum or plate, and so set as to keep an even pres-

page_text: sure on the paper, these springs or studs being in connection with the test or
line circuits, as hereinafter explained.
In order to apply our invention to a multiple telephonic exchange switch-board,
the line commonly known as the test-wire, must be extended, and connected to
a spring or pointer, which lightly presses on a slip of paper, saturated with a
chemical solution, (such as iodide of potassium and starch, or ferrocyanide of
potash) which will readily decompose under the influence of an electric current,
the paper slip being carried forward at a predetermined rate. As soon as the
operator at the exchange inserts a plug into a subscriber's jack, a current is put
on the test-wire, which not only serves as a signal to the other operators that
the line is in use, but also decomposes the chemical in the paper strip, thus
automatically recording the exact moment at which the plug was inserted, and
continuing the record until the plug is withdrawn.
66
Our invention may also be used on boards where what are commonly known as
make-and-break jacks" are in use. Under such circumstances, we prefer that
the method of recording the calls, as described, be reversed, that is to say, that
so long as the line of the subscriber is disengaged, the current flows over the
recording spring, and marks on the prepared paper, but as soon as the plug is
inserted in the jack, such marking ceases. In this modification, the connections
must be slightly altered, and, instead of the test-wire being extended, the con-
nection may be taken from the centre-point of the line indicator to the recording
spring, the battery being placed between the earth and the drum or plate over
which the prepared paper travels.
It is also necessary, in this case, to earth the centre-point of the bell at the
sub-station.
Our invention may be further adapted to single-cord boards by so arranging
the connections at the plug socket that the circuit between the plug socket and
the spring on the recording instrument is opened or closed according to the
method of working adopted, so that the desired record is made until the plug is
returned to the socket.
Our invention may also be adapted to night-watchmen's tell-tale systems, by
replacing the clock, as heretofore used, by an electrical switch, which closes the
circuit for a pre-arranged period, thus indicating on the recording apparatus,
provided for that purpose, the time of the watchman's visit. It may also be used
by railway companies for recording the number of times the points or signals
are moved; likewise the length of time they remain in any position on any particu-
lar line of rails.
To enable our invention to be clearly understood in its various modifications,
reference should be made to the accompanying drawings:-
-
Fig. 1. shows our invention applied to a telephonic multiple switchboard with
branching jacks and self restoring indicators.
Fig. 2. represents the application of our invention to a telephonic multiple
switchboard in which break jacks with make-and-break test circuit are used.
Fig. 3. is a diagrammatic representation of one method of passing the chemically
treated paper under the recording spring or stud.
Fig. 4. is a plan showing a method of arranging a number of recording springs
so that the greatest number of records may be taken on a minimum width of
paper.
Figs. 5. & 6. show the application of our invention to junction lines and
duplex circuits.
:
The
In Fig. 1, is shown the exchange apparatus of three subscribers lines A, B, and C,
multiplied through two sections of a switchboard on a branching system with
self restoring indicators. The spring jacks a & a¹ b and b, c & c¹ and indica-
tors, & are connected together in the usual well known manner.
connections of the self restoring coils d, d & d and the test rings r, rl etc. are
modified in the following manner: -One pole of the restoring battery D is con-
nected through the coil in the usual way, the other side of the coil, in addition

page_text: to being connected to the test rings r etc. is joined by means of wires e, e¹ etc. to
metal springs f, f¹ etc. which press on a revolving metal drum E, the speed of
this drum being controlled by clockwork.
In order to simplify the description of our invention we will explain the con-
nections of the recording circuit in relation to exchange apparatus of subscriber A
only. On the insertion of a plug into jack a or a¹ the current from the battery D
finds a path through wire g restoring springs h & h' which are joined together
by means of the ring of the connecting plug, wire k or k¹ bush or 1 wire e, to
spring which presses on the recording drum E, and through common return m,
resistance R, common return n to battery D. This current will continue to flow
so long as a plug is inserted, decomposing the chemical with which the recording
paper is saturated. This paper travelling at a predetermined rate and being
divided into definite spaces records the exact time and duration of the connection.
In Fig. 2, where the jacks used are of the make-and-break type, the method
of recording the duration of the connection may be the reverse of that described for
Fig. 1, .e. a continuous mark is made on the prepared paper when the line is
disengaged, and the act of inserting the plug breaks the circuit, thus also break-
ing the continuity of the record mark. In this modification the centre points of
the subscribers' instruments are connected to earth when the receiver is on the
switch-hook, and the centre points of the line indicators at the exchange are con-
nected to the recorder as in the previously described method. The recording
circuit is as follows:-From the earthed common battery at the exchange, through
recorder to centre point a of line indicator A, through the coils in parallel, through
all jacks B of that line in series, over lines c & c¹ in parallel, through bell
coils D, in parallel to the centre point, and thence through contact on switch-
hook to earth. Thus, so long as the subscribers' receiver remains on the switch-
hook a continuous line is made on the recording paper, and the removal of the
receiver during conversation breaks the recording circuit so that the duration of
the connection is indicated by the length of the space.
In Fig. 3, A is the recording spring connected either to centre point of the
line indicator as in Fig. 2, or to the test circuit as in Fig. 1, 13, is a metal roller
over which the recording paper passes. This roller is in the recording circuit
and may be driven by clockwork. C, is a small tank containing the fluid for
moistening the paper, E, and F, are drums driven by clockwork for drawing the
recording paper forward.
In Fig. 5, A & B are two junctions or trunk lines, C, is the superimposed or
extra circuit, D, D, are differentially wound bridging coils from the centre points
of which the extra circuit is obtained, F, F, are the plugs for connecting the
junctions or trunks to subscribers' lines. G, G, are socket contacts connected to
the recorder and so arranged that when the plug F, is in the position of rest the
line to the recorder is insulated. As soon as the plug is removed from the socket
the circuit is completed and the recorder indicates.
In Fig. 6, A & B are two junction or trunk lines, C, is the superimposed
or extra circuit, D, D, are differentially wound translators from the centre points
of which the extra circuit is obtained. H, may be an ordinary translator, J, J, are
make-and-break jacks connected in series to their respective lines; the inner con-
tacts of the last jacks are connected respectively to earth and to the recorders.
In this modification the record is taken by breaks in the line on the record paper.
This invention admits of modification in the arrangements, which would readily
suggest themselves to those skilled in the art. I therefore do not limit myself to
the precise arrangements shown and described herein.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare what we
claim is:
-
1. The improved method of automatically recording the number and duration
of the messages transmitted over telephonic and telegraphic or other signalling

page_text: circuits herein before described under several modifications with reference to the
annexed diagrams.
Dated this 16th day of March 1898
DANIEL SINCLAIR.
WILLIAM JAMES GRAY.