An Improved System of Recording Telephonic Messages.
Year: 1898

page_text: Date of Application, 7th Sept., 1898
Complete Specification Left 31st May 1800_Accented 20th July 1800
An Improved System of Recording Telephonic Messages.
I, WILLIAM AITKEN, Engineer to the National Telephone Company Limited,
of Oxford Court, Cannon Street, in the City of London, do hereby declare the
nature of this invention to be as follows:-
This invention has for its object a method of recording the number of calls
a subscriber originates over a telephone exchange system, particularly in connec
tion with exchange systems using an earthed battery for clearing purposes, and
this without any special act on the part of either the subscriber or the operator.
At the subscriber's office is fitted any of the wellknown patterns of instruments
altered as follows:---
The switch-hook as well as performing its usual functions operates a switch
which when the instrument is at rest joins the A wire of the metallic circuit
line through the bell of the instrument to earth (preferably the bell should be
wound to a high resistance or a resistance coil inserted in the earth before men-
tioned) and joins the B wire which has been already passed through a plunger
switch, through a galvanometer, and two polarised relays joined in parallel or
series, to earth.
The plunger switch mentioned above consists of a spring which can be depressed
by a plunger; this spring normally makes connection with an upper contact
which joins the line through the before mentioned apparatus to earth. When
the plunger is depressed the spring leaves the upper contact and makes and breaks
connection with a series of earth contacts. This switch is to be used only when
any difficulty is experienced in getting connection, as will be further described.
The galvanometer is provided to show the subscriber when the line is clear for
a second connection and may be of any of the well-known simple forms.
One polarised relay is for recording purposes and responds to the clearing cur-
rent when the receiver is placed on the switch-hook, the relay then actuating a
train of wheels which causes a pointer to step forward one division of a dial
each time this is done.
The second relay is a non-recording one and is double wound and has two
armature extensions, and is also polarised, and responds first to the ringing relay
current, which is of different polarity to the clearing current. This current causes
a toothed block to move one step, in which position it is held by a pawl. When
the ringing current is removed the armature recovers and brings the second
winding into circuit; this is opposite in direction to the former one and when
the receiver is placed on the switch-hook the clearing current makes the relay and
the toothed block take a second step. When the plugs are withdrawn and the
clearing current thereby removed the relay returns to the normal position, no
record is therefore made at the instrument of the subscriber who has been called.
The first movement of either relay cuts the other out of circuit.
No alteration or addition is necessary at the exchange.
This arrangement although perfectly workable is subject to abuse as the calling
subscriber by refraining from putting his receiver on the switch-hook until his

page_text: galvanometer needle returns to the vertical, i.e., until the subscriber he has been
in connection with has placed his telephone on the switch-hook, thereby giving
the clearing signal and the operator has withdrawn the plugs can prevent his
instrument from recording. To meet this objectionable feature, I preferably use
the following modification. At the subscriber's station any of the well-known
forms of instruments may be used fitted as before described with a switch worked
by the switch-hook, plunger switch and galvanometer joined in the circuit as
before described, and one polarised relay joined in the place of the two formerly
described.
At the exchange I divide the cords into two sections, preferably by condensers,
as they allow speech currents to be transmitted without appreciable loss, and
yet prevent signals with earthed battery being affected by an earth on the other
side. One condenser is placed in the A line and another in the B line between
the answering and calling plugs. The answering plug circuit is bridged by
(1st) a differentially wound retardation coil of high resistance and self induction
with the centre point joined to a battery indicator or relay with lamp in the local
circuit, which in turn is joined to an earthed battery, the battery being
connected in such a way that it will actuate the relay at the subscriber's office
when the receiver is returned to the switch-hook after a conversation, or, (2nd) the
differential coil may have an indicator combined with it and the resistance of the
bell circuit of the subscriber's instrument be so increased that a preponderance
of current will pass over the B wire of the metallic circuit and through one half
of the differentially wound coil, this difference being sufficient to actuate the
armature of the indicator and give the clearing signal.
A similar arrangement is connected to the calling cord circuit in addition to
the ordinary listening key and ringing relay, the battery in this case, however
being connected with the opposite pole to line so that the relay at the sub-
Ecriber's instrument will not respond when the receiver is returned to the switch-
hook after a conversation, as the answering subscriber is not to be charged.
The working of the system will be as follows:-A subscriber desiring connec-
tion will call in the usual way (the lifting of the receiver removing the earth
connection from the instrument). The operator will answer, test the line wanted,
connect and ring the subscriber wanted in the usual way.
If the subscriber wanted will not reply the subscriber calling can get the
attention of the operator by depressing the plunger switch, which will cause the
indicator in the answering cord to vibrate.
When conversation is finished and the clearing signals given, the recording
apparatus at the originating subscriber's instrument will also have recorded one
message. As there is a clearing signal for each subscriber connected the operator
will not withdraw the plugs until both have given the signal.
A second connection must not be asked for until the galvanometer needle returns
to the vertical or confusion and false recording will arise.
Dated this 7th day of September. 1898.
WILLIAM AITKEN.
An Improved System of Recording Telephonic Messages.
I, WILLIAM AITKEN, Engineer to National Telephone Company, Limited,
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:-
This invention has for its objects a method of recording the number of calls a

page_text: subscriber or renter originates over a telephone exchange system, particularly in
connection with exchange systems using a battery for clearing purposes, and this
without any special act on the part of either the subscriber or the operator.
The object of this invention is obtained by the following means:
By arranging the circuits of two subscribers' lines joined together at an
exchange, in two parts by translators on condensers, with a clearing battery of
opposite polarity in each section, that in the calling subscribers circuit only
actuating the polarised electromagnetic relay of the recorder or counter.
My invention is illustrated by the accompanying drawings.
Fig. 1 of which is a diagrammatic representation of the circuits and of the
apparatus at the central and sub-stations in connection with a telephonic exchange
system using an earthed battery joined to the centre points of bridging coils in
the cords at the central and an earth at the sub-station when the telephone is on
its rest.
Fig. 2 is a diagrammatic representation of the circuits and of the apparatus
at the central and sub-stations in connection with a telephonic exchange system
using batteries in combination with translators or transformers at the central and
a condenser or open circuit at the sub-station to prevent the batteries at the central
discharging when the lines are not in use.
In the arrangement shown in Fig. 1, the subscriber's office is fitted with any of
the well-known patterns of instruments fitted with polarised ringers and generators
altered as follows:
The switch-hook e as well as performing its usual functions operates a
switch which when the instrument is at rest joins the centre point of the bell i
of the instrument (preferably the bell should be wound to a high resistance or a
resistance coil inserted in the earth before mentioned) through a plunger switch k,
through a galvanometer 1, and polarised relay joined to earth.
The plunger switch & mentioned above consists of a spring which can be
depressed by a plunger; this spring normally makes connection with contact ²
which joins the line through the before-mentioned apparatus to earth. When the
plunger is depressed the spring leaves the contact and makes and breaks
connection with earth contact p.
This switch is to be used only when any difficulty is experienced in getting
connection, as will be further described, and should be so constructed that the
contacts are made as the plunger is depressed and beyond the control of the
subscriber.
The galvanometer is provided to show the subscriber when the line is clear
for a second connection and may be of any of the well-known simple forms. Instead
of this the relay armature may show a flag signal, which will indicate the same
thing.
The polarised electromagnet n is for recording purposes and responds to a
current of one polarity only when the receiver is placed on the switch-hook.
The electromagnet actuates a train of wheels which causes a pointer to step
forward one division of a dial each time a suitable current passes through the
coils.
At the exchange I divide the cords into two sections, by condensers t, t¹, as they
allow speech currents to be transmitted without appreciable loss, and yet prevent
signals with earthed battery being affected by an earth on the other side. One
condenser is placed in the A line and another in the B line between the answer-
ing and calling plugs. The answering plug circuit is bridged by a differen-
tially wound retardation coils of high resistance and self induction with the centre
point joined to a battery indicator 2 or relay with lamp in the local circuit, which
in turn is joined to an earthed battery z, the battery being connected in such a way
that it will actuate the electromagnet at the subscriber's office when the receiver d
is returned to the switch-hook c after a conversation.
A similar arrangement is connected to the calling cord circuit in addition to
the ordinary listening key and ringing relay w, the battery in this case, how-
ever, being connected with the opposite pole to line so that the electromagnet n at

page_text: the called subscriber's instrument will not respond when the receiver is returned
to the switch-hook e after a conversation as the answering subscriber is not to
be changed.
The working of the system will be as follows:-A subscriber desiring connec-
tion will call in the usual way (the lifting of the receiver removing the earth
connection from the instrument). The operator will answer, test the line wanted,
connect, and ring the subscriber wanted in the usual way.
If the subscriber wanted will not reply the subscriber calling can get the atten-
tion of the operator by depressing the plunger switch which will cause the
indicators in the answering cord to vibrate.
When conversation is finished and the clearing signals given, the recording
apparatus at the originating subscriber's instrument will also have recorded
one message. The current then being from earthed battery through indicator så
centre point of bridging coils to tip and ring of plug r, to a¹ & springs of jack c
over the A & B wires in parallel, through the two bell coils in parallel to centre
point, to galvanometer and through coils of counter or recorder to earth.
Armature m is thereby attracted carrying the wheels and pointer to one division,
the armature remaining attracted until the plugs are withdrawn. The circuit
on the called sub-station line is similar but as the current is of opposite polarity
the recorder is not affected.
As there is a clearing signal for each subscriber connected the operator will
not withdraw the plugs until both sub-stations have given such signal.
A second connection must not be asked for until the galvanometer needle returns
to the vertical or confusion and false recording will arise.
For the arrangement shown on Fig. 2:
In addition to the ordinary subscribers instrument used with what is known
as the common battery system I place in parallel with the microphone V and the
primary of the induction coil the polarised relay r and a polarised electro
inagnetic counters both of which will only respond to one direction of current.
The relay and the counter s may be combined. The switch-hook y as it ascends
and descends presses the armature against the core and contact of relay r. The
relay and counter coils s and relay must be of such resistance that the clearing
relay will not remain sufficiently energised to close the local circuit.
At some
convenient point on the circuit a switch % is introduced which should be so con-
structed that the lever cannot rest on any contact or be held in a position that
will insulate the line while the receiver ¹ is being placed on the switch-hook.
To avoid disagreeable clicking the lever should short circuit the receiver when
depressed.
At the exchange I use two batteries g & g¹ on the translators or transformers hi
in the cords. The battery g in the answering plug m circuit being so connected 4
that it will actuate the counters and relay at the subscribers office, the other
battery g being common to the line signal e and the calling plug n circuit do not
operate the counter s or relay r.
The translator winding his connected to the battery g¹ through the armatures
and contacts of a double tongue relay the inner contacts of which are joined
to battery or to opposite poles of battery g' as shown. The coil of relay j has
one side joined to earth and the other side to the bush or barrel c of the spring
jack k. The springs a &b of jack kare joined to the buzzer or phonograph
which gives the engaged signal to the subscriber calling. One jack is provided
for each pair of cords.
.
The working of the system will be as follows:-The calling subscriber will
lift the receiver el from the switch-hook g in the usual way to call but the counter s
is not affected by the battery g. The operator answers, tests, and if the line
wanted is disengaged connects in the usual way and rings the subscriber wanted,
the plug m then being in jack and plug n in jack . (For the sake of clearness
the listening and ringing keys and operators telephone are not shown.) When
conversation is finished both subscribers hang the receivers on the switch-

page_text: hooks & The counter circuit of the calling line as the switch-hook, q
descends to position q is from one side of battery g through one half of one
winding of translator h to tip of plug m, to spring of jack over the A wire
of the metallic circuit through switch at sub-station C through armaturer and
contact and coil of relay through coil of counters to B wire (the condenser
breaking the circuit through bell), to spring of jacka, wing of plug m through
clearing relay O and half coil of one winding of translator to other side of
battery . The armature of relay r and armatures of counter s remain
attracted and flag signal shows the line engaged until the operator withdraws
the plug m then they all return to the normal condition. One end of the arma-
ture of the counter, s is weighted so that when descending it causes the arm t¹ to
make the train of wheels t take one step and the pointer on the dial then indicates
one call. While the flag signal u shows through the opening provided the sub-
scriber must not ask for a second connection. The circuit through sub-station D
is similar to that just described but as the current is opposite in direction the
relay and counter coils are not energised.
If sub-station called for sub-station 1) and the latter was already engaged,
the operator would insert plug n in jack k (plug m being in jack a) this would
give the engaged signal to sub-station C and reverse the battery g¹ so that when
the receiver was placed on the switch-hook the counters would not be
affected. The circuit is from earth of battery g¹ to sleeve of plug n to bush c of
jack through coil of relay to earth.
Should the operator not reply promptly or should a wrong connection be made
the subscriber must call the operator's attention by moving lever or plunger of
switch, this breaks the circuit intermittently and causes the lamp p to pulsate.
(The circuit of this lamp is from earthed battery g through lamp p, sleeve of
plug m, spring of jack & through coil of cut-off relay to earth E.) The
operator will not withdraw the plug as the clearing signal is a steady glow, but
will speak to the subscriber.
C
The calling subscriber must on no account place the receiver on the switch-
hook until he has finished his conversation.
This invention admits of modifications 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 or described herein.
Having now particularly described and ascertained the nature of my said
invention, I declare that what I claim is;-
-
(1) The improved system of automatically recording the calls or messages made
by a subscriber or renter to a telephonic exchange system, substantially as
described.
(2) The combination of a counter or recorder with a polarised relay whose
circuit is mechanically closed by the switch-hook of a telephone instrument and
remains held closed by a current of suitable polarity from a battery at the central
station until the plugs are withdrawn.
(3) The combination of a counter or recorder with or without a relay with a
switch which enables the subscriber or renter to rectify mistakes without affecting
the recorder, at the sub-station substantially as described.
(4) The division of the cords at the central station by condensers or trans-
lators with a battery of opposite polarity in each section so arranged in
combination with counters or recorders at the sub-stations that only the counter
or recorder at the calling sub-station will record a message when the receivers
are placed on the switch-hooks substantially as described.
(5) The combination of a busyback spring jack with each pair of cords with a
relay which reverses the battery on the answering cord, thus enabling the calling
sub-station to replace his receiver on the switch-hook after the operator has
signalled that the line wanted is engaged substantially as described.
(6) A switch at the sub-station which when operated, intermittently earths or

page_text: breaks the circuit causing the lamp or battery indicator at the central to be inter-
mittently energised and therefore giving to the operator there a distinctive signal
which cannot be mistaken for a clearing signal but which indicates that the
operator must again cut her instrument into circuit and learn the further require-
ments of the sub-station, substantially as described.
(7) A switch at the sub-station which when operated intermittently earths or
breaks the circuit causing the lamp or battery indicator at the central to be
intermittently energised and at the same time short circuits the receiver at the
sub-station so that there is no disagreeable clicking in the ear of the subscriber
at the sub-station substantially as described.
WILLIAM AITKEN.