IMPROVEMENTS IN ELECTRIC TELEGRAPHS "
Year: 1881

page_text: LETTERS PATENT to Sir James Anderson of 66, Old Broad Street in the City
of London and Benjamin Smith of Princes Street Hanover Square in the
County of Middlesex for an Invention of "IMPROVEMENTS IN ELECTRIC
TELEGRAPHS "
PROVISIONAL SPECIFICATION left by the said Sir James Anderson and
Benjamin Smith at the Office of the Commissioners of Patents on the
20th December 1881.
Sir JAMES ANDERSON of 66 Old Broad Street in the City of London and
BENJAMIN SMITH of Princes Street Hanover Square in the County of Middlesex
IMPROVEMENTS IN ELECTRIC TELEGRAPILS
"
"
"
This Invention has for its object improvements in electric telegraphs and relates
more especially to the means of and apparatus for retransmitting or translating
telegrams from one telegraph cable or telegraph line to another. Our improve-
ments render fewer the operators to be employed and expedite the transmission
of telegrams.
At intermediate cable stations, such, for example as Aden, which is connected on
the one hand with Suez, and on the other with Bombay, it has heretofore been
usual that each cable should have a separate and complete set of instruments, and
the two cables have been independently worked. Thus a telegram received at the
intermediate station is usually written out by an operator at one cable and given
to the operator at the other cable for retransmission.
Our Invention is not confined to the working of cable lines but is equally
applicable to land lines whether aerial or subterranean but for convenience of
description we shall speak of the Invention as applied to a cable line. Neither is
it essential to our Invention that recording instruments should be employed for
other receiving instruments may be made use of, but for convenience of description
we shall style the receiving instrument the recorder.
According to our Invention we are able to employ one set of instruments, one
key and one recorder for the two cables, and for this purpose we employ a novel

page_text: switch having a lever handle which has three positions. In the central position of
the handle both cables (or the condensers into which the cables work if such be
employed as is usual) are connected through the recorder to earth, and in this
position a call signal sent through either cable is received upon the paper of the
recorder.
When the handle is moved to either side one cable remains connected with the
recorder whilst the other becomes connected with the key and through the key
with the battery.
The operator then on receiving a call moves the handle over from the central
position to that side which leaves the calling station connected with the recorder
and as the telegram comes in he reads it from the paper of the recorder and
retransmits it by means of the key into the other cable. When the handle of the
switch is moved over to the other side the connections are reversed and become
suitable for working in the opposite direction through the cables
The same movement of the handle alters the buttery from what is suitable for
one cable to that which the other cable requires.
This novel translation switch consists of the handle already referred to and two
levers one on either side of it and which are in electrical connection with the
cables each to each.
When the handle is central the levers rest against their stops and through them
are connected with the recorder and this has a permanent earth connection. When
the handle is moved to either side one or other-of-the-levers-is-lifted-from-its-stop,
whilst the other lever remains. On the side where the lever is lifted the con-
nections may be traced from the lever through the handle to a block on which the
handle then rests thence to the key and earth, or on a key being depressed, the
battery is included in the circuit.
The battery connection is through a pair of springs on the switch which when
the handle is put over are pressed and held together. When the handle is put over
to the other side these springs separate and other corresponding springs on the
other side are held together thereby changing the battery and in either case putting
on the battery proper to the cable into which the key currents pass.
If it be desired to apply a second recorder to record the retransmitted signals as
they go out this can be done, the second recorder suitably shunted is introduced
between the switch and the key.
Another way in which we can effect the same object is by connecting electrically
the two cables the recorder, and the transmitting key, with a "Wheatstone's Bridge
Arrangement." In the direct connection from cable to cable (or between the con-
densers into which the cables work) the recorder is placed whilst the key is
connected with the cables by the two resistances which complete the bridge. Thus
the outgoing or key currents are balanced so as not to influence the recorder, which
however responds to incoming currents from either cable.
In this arrangement the positions of the transmitting key and recorder are inter-
changeable and condensers may be substituted for resistances.
In place of employing a "Wheatstone bridge arrangement" a differentially wound
receiving instrument may be employed.
In some cases we arrange the apparatus so that each cable being provided with
its own recorder switch and transmitting key for independent working, the con-
nections can at pleasure be changed so that the key of one cable is made available
for retransmitting into the other cable.
Each switch like the switch already described consists of a handle having three
positions, a middle position and two side positions, the latter being respectively the
sending and receiving positions.
In the middle position the cable, (or the condenser into which it works where
such a condenser is employed) is connected to earth both through the shunt and
the recorder.
When the handle is in the receiving position the cable (or condenser) is to earth
through the recorder only.

page_text: When the handle is in the sending position the key is brought in and the
currents originated by it pass to the cable (or condenser) both by the shunt and
the recorder which then keeps a record of the outgoing signals. By means of peg
commutators the connections of the keys can be changed so that the key properly
belonging to one set of instruments becomes temporarily the key of the other set.
Thus an operator as he reads an incoming telegram on his own recorder, can
retransmit it at once by the other cable.
A record of the outgoing signals is kept upon the second recorder. For working
in the contrary direction all that is required is to move the switch handles over
and to alter the positions of the pegs in the commutators. Also the two cables
can be rendered wholly independent by changing the positions of the pegs of the
commutators.
The switch is provided with two contact levers one of which is earth connected,
the other being connected with the shunt and also with an insulated stud. Tho
handle is always connected with the line either through the recorder or otherwise.
Both the levers rest against the handle when this is in the middle position, but the
handle leaves the earth lever, when it is put over to the sending side, and it leaves
the shunt lever when it is put over to the receiving side.
There are also metallic blocks upon which the switch handle makes contact in
its several positions. A central block on which it rests in the middle position is
connected to earth, as is also a block on one side thereof on which the handle rests
in the receiving position--this connection to earth may either be direct or through
a receiving instrument. On the other side is a block which is connected with the
key and the shunt. The handle when in the sending position rests both upon this
block and upon the insulated stud already mentioned in connection with the shunt
and so it couples the shunt as well as the recorder with the key.
Where the two cables are duplexed also we arrange so that a message as it is
received by one cable may be read off the instrument and as it is read retrans-
mitted or translated into the other cable. We provide for this purpose peg
commutators by which the keys can be changed in their connections from one cable
to the other, and in addition we provide for changing the earth connection of the
key so that each cable may always be worked with the same earth connection,
usually its own sheathing wires.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sir James Anderson and Benjamin Smith in the Great Seal
Patent Office on the 20th June 1882.
Sir JAMES ANDERSON of 66 Old Broad Street in the City of London and
BENJAMIN SMITH of Princes Street Hanover Square in the County of Middlesex
"IMPROVEMENTS IN ELECTRIC TELEGRAPHS
33
This Invention has for its object improvements in electric telegraphs and relates
more especially to the means of and apparatus for retransinitting or "translating
telegrams from one telegraph cable or telegraph line to another. Our improve-
ments render fewer the operators necessary to be employed and expedite the trans-
mission of telegrams.
At intermediate cable stations, such for example as Aden which is connected on
the one hand with Suez and on the other with Bombay, it has heretofore been
usual that each cable should have a separate and complete set of instruments; and
the two cables have been independently worked. Thus a telegram received at the
intermediate station is usually_written_out_by an operator at one cable and given
to the operator at the other cable for retransmission.
Our Invention is not confined to the working of cable lines but is equally
applicable to land lines whether aerial or subterranean but for convenience of
description we shall speak of the Invention as applied to a cable line. Neither is
it essential to our Invention that recording instruments should be employed for
other receiving instruments may be made use of but for convenience of description
we shall style the receiving instrument the recorder.
According to our Invention we are able to employ one set of instruments one
key and one recorder for the two cables; and for this purpose we employ a novel
switch having a lever handle which has three positions. In the central position of
the handle both cables (or the condensers into which the cables work if such be
employed as is usual) are connected through the recorder to earth and in this
position a call signal sent through either cable is received upon the paper of the
recorder.
When the handle is moved to either side one cable remains connected with the
recorder whilst the other becomes connected with the key and through the key
with the battery.
The operator then on receiving a call moves the handle over from the central
position to that side which leaves the calling station connected with the recorder
and as the telegram comes in he reads it from the paper of the recorder and
retransmits it by means of the key into the other cable. When the handle of the
switch is moved over to the other side the connections are reversed and become
suitable for working in the opposite direction through the cables.
The same movement of the handle alters the battery from what is suitable for
one cable to that which the other cable requires.
This novel translation switch consists of the handle already referred to and two
levers one on either side of it and which are in electrical connection with the
cables each to each. When the handle is central the levers rest against their stops
and through them are connected with the recorder and this has a permanent earth
connection. When the handle is moved to either side one or other of the levers is
lifted from its stop whilst the other lever remains. On the side where the lever is
lifted the connections may be traced from the lever through the handle to a block
on which the handle then rests; thence to the key and earth, or on a key being
depressed the battery is included in the circuit.
The battery connection is through a pair of springs on the switch which when

page_text: the handle is put over are pressed and held together. When the handle is put
over to the other side these springs separate and other corresponding springs on
the other side are held together thereby changing the battery and in either case
putting on the battery proper to the cable into which the key currents pass.
If it be desired to apply a second recorder to record the retransmitted signals as
they go out, this can be done; the second recorder suitably shunted is introduced
between the switch and the key.
Another way in which we can effect the same object is by connecting electrically
the two cables, the recorder and the transmitting key, with a Wheatstones Bridge
arrangement. In the direct connection from cable to cable (or between the con-
densers into which the cables work) the recorder is placed whilst the key is con-
nected with the cables by the two resistances which complete the "Bridge." Thus
the outgoing or key currents are balanced so as not to influence the recorder which
however responds to incoming currents from either cable.
In this arrangement the positions of the transmitting key and recorder are
interchangeable and condensers may be substituted for resistances.
In place of employing a "Wheatstone Bridge" arrangement a differentially
wound receiving instrument may be employed.
In some cases we arrange the apparatus so that each cable being provided with
its own recorder switch and transmitting key for independent working, the con-
nections can at pleasure be changed so that the key of one cable is made available
for retransmitting into the other cable.
Each switch, like the switch already described consists of a handle having three.
positions, a middle position and two side positions; the latter being respectively
the sending and the receiving positions.
In the middle position the cable (or the condenser into which it works where
such a condenser is employed) is connected to earth both through the shunt and
the recorder.
When the handle is in the receiving position the cable (or condenser) is to earth
through the recorder only.
When the handle is in the sending position the key is brought in and the
currents originated by it pass to the cable (or condensor) both by the shunt and
the recorder which then keeps a record of the outgoing signals. By means of peg
commutators the connections of the keys can be charged so that the key properly
belonging to one set of instruments—becomes temporarily the key of the other set.
Thus an operator as he reads an incoming telegram on his own recorder can
retransmit it at once by the other cable.
A record of the outgoing signals is kept upon the second recorder. For working
in the contrary direction all that is required is to move the switch handles over
and to alter the positions of the pegs in the commutators. Also the two cables
can be rendered wholly independent by changing the positions of the pegs of the
commutators.
The switch is provided with two contact levers one of which is earth connected
the other being connected with the shunt and also with an insulated stud. The
handle is always connected with the line either through the recorder or otherwise.
Both the levers rest against the handle when this is in the middle position, but the
handle leaves the earth lever when it is put over to the sending side and it leaves
the shunt lever when it is put over to the receiving side.
There are also metallic blocks upon which the switch handle makes contact in
its several positions. A central block on which it rests in the middle position is
connected to earth, as is also a block on one side thereof on which the handle
rests in the receiving position this connection may either be direct or through
a receiving instrument. On the other side is a block which is connected with the
key and the shunt. The handle when in the sending position rests both upon this
block and upon the insulated stud already mentioned in connection with the shunt
and so it couples the shunt as well as the recorder with the key. Where the two
cables are duplexed also we arrange so that a message as it is received by one

page_text: The recorders are in each case connected with the receiving condensor on the one
side and the handle of the switch on the other.
When the switch handle is in the middle position as shewn the recorder is
connected through the handle to earth, the handle piece resting on the earth
connected block q. The shunt is also carth connected through the side lever s,
the handle p and the block q. When the handle is moved to the right which is
the receiving side it rests upon another connected block t but the handle piece
has passed out of contact with the lever 8 and the shunt circuit is broken.
By passing the handle over to the left it is brought in to contact with the block u
which is connected with the transmitting key as is shewn and also into contact
with the stud v connected with the shunt so that the key currents are divided
part going along the handle to the recorder and part going by the lever s to the
shunt. The connections for the most part are double whereby the risk of bad
contacts is greatly lessened. wware peg commutators, by shifting the pegs the
transmitting keys are as will be seen in effect changed over from the one cable to
the other.
Figure 9 shows the arrangement we employ at an intermediate station where
two duplexed cables meet.
The duplexing is effected by well known means which will be clearly understood
from the Figure.
X' and X2 are the two keys at the intermediate station; the key X¹ properly
belongs to line 1 and the key X to line 2. For so working the cables separately
pegs will be placed in the holes 1 and 3 of the two commutators Y' and Y'
thereby completing the connection of each key with its own cable and the earth
belonging to this cable. For translating the pegs are transferred to the holes 2
and in the commutators Y' and Y2 which in effect transfers each key from one
cable and earth to the other.
Having thus described the nature of our said Invention and the manner of
performing the same we would have it understood that we claim :-
First. The combination with two telegraph circuits of one set of instruments a
recorder or other receiving instrument a transmitting key and a switch; the whole
being so arranged that messages arriving by either cable may be received on the
same recorder or receiving instrument and forwarded by the key along the other
cable substantially as described in respect to Figures 1 and 2 of the Drawings
annexed.
Second. The improved switch substantially as described by Figures 3 and 4 of
the Drawings annexed.
Third. The method of combining two telegraph circuits by a "Wheatstone
Bridge" or differential arrangement with a transmitting key and recorder or other
receiving instrument interposed so that the recorder registers signals arriving by
either cable and is unaffected by the operation of the key substantially as described
in respect to Figures 5, 6 and 7.
Fourth. The improved switch substantially as described in respect to Figure 8.
Fifth. The combination of apparatus for the conjoint working of two duplexed
cables substantially as described in respect to Figure 9.
In witness whereof I the said Benjamin Smith have hereunto set my hand
and seal this Fifteenth day of June in the year of our Lord One thousand
eight hundred and eighty two.