Improvements in or relating to Electric Telephone Systems.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Electric Telephone Systems.
We, THOMAS SLOPER of 14 Brittox Devizes in the County of Wilts House
Furnisher and GEORGE EDMUND BECKETT of 29 Andrews Street Leicester in the
County of Leicestershire Electrician do hereby declare the nature of this invention
to be as follows:-
This invention relates to certain improvements in electric telephone switches or
systems & more particularly to that class of telephones used in warehouses factories
& other places where a number of rooms or stations are situate close together.
The invention relates to certain improvements or modifications of the system
described in the British Letters Patent No. 13,367 of the year 1891 which Patent
was granted to Thomas Sloper & dated August 7 1891.
A line wire is used for each station in addition to the "earth" or return wire &
each line wire is connected to a stud on the switch of the instrument at each station.
In the case of the instrument to which the line belongs (which line we will call the
"home" line) the line is not connected to the switch as the others but it is connected
through a Morse key (which key we will call B.) to the telephone.
Between the Morse key & the telephone a branch line is connected to one terminat
of the call bell.
The usual switch hook upon which the receiver is hung when not in use is
employed & this is connected permanently to the "earth or return line. When
the receiver is hung up this switch hook makes contact with a spring or equivalent
device which is in metallic connection with the second terminal of the call bell.
The switch hook also makes or breaks the circuit of the microphone & primary
coil in the usual manner where such are employed.
Attached to the switch hook but, permanently insulated from it is a strip of
metal. When the receiver is taken off its hook this strip of metal makes contact
with & electrically connects two separate metallic springs.
One of these spring
is permanently connected to the telephone receiver (through the secondary of
the induction coil where one is used) and the other spring is connected to the
switch or other device for connecting to the line wires of the other stations.
Between the latter spring & the switch is a press button or Morse key which we
will call "A" key.
When this key is pressed it comes in contact with a stud which is connected to
the battery & a current is sent through the switch to the line & instrument of which
other station the switch is at the time connected to.
Any suitable form of switch may be employed, but for convenience we prefer to
use a metal arm pivoted at one end & so arranged that the other end is free to be
turned round & so to be brought into contact with any one of the studs connected
with the lines of the other stations.
In addition to these studs in connection with the line wires we sometinies use one
other stud on each instrument. These studs are marked " reply & are all
connected together by a special line wire which we call the "reply" wire.
A wire connects the reply stud on each instrument to the bottom contact of the
above mentioned Morse key B and the arrangement is such that when this key B
is pressed in, the "home" line is disconnected & the connections joining the Morse

page_text: key from the telephone & the call bell respectively are transferred to the reply line
from the home line.
The working of the instruments is as follows-Suppose a person at No. 5
instrument wishes to communicate with No. 3 he first puts his switch on No. 3
stud & presses the key "A" which sends a current to No. 3 station.
This current arriving through the home line at No. 3 station passes through the
Morse key to the call bell, & to the earth or return line through the switch hook.
In addition to pressing his key A the person at the "calling" station presses his
key B until he hears his own bell ring & has informed the person at the "called
station of the number of his station.
66
"
"
The person at the " called station upon hearing his bell ring, places his switch
on the stud marked "reply " & presses hi- key A which rings the bell at the calling
station. He then listens at his receiver until he is informed the number of the
calling station when he places his switch to that number & the connections are
complete. Conversation can then be carried on without any possibility of cross-talk
occurring with other stations on the system. In order that the "called " station
shall not press his key B in mistake we so arrange that when the switch is at
reply" this key cannot be used. If no reply ring is required the special reply
line may be omitted & the reply stud connected to the terminal of the ordinary
In this case the operation is the same except that the person
at the calling station listens at his receiver instead of waiting until his bell rings.
It will be understood that the ringing current from the calling station goes
through the "home" line of the called station & returns through the return or earth
wire. When the extra reply line is used the speaking is first through the home line
of the called station returning by the reply line until the called station knows what
station is calling & it is then through the home lines of the two speaking stations
the earth or common return lines being cut off.
return or earth line.
Dated this 22nd day of May 1895.
THOMAS SLOPER.
GEORGE EDMUND BECKETT.
COMPLETE SPECIFICATION.
Improvements in or relating to Electric Telephone Systems.
We, THOMAS SLOPER of 14 Brittox Devizes in the County of Wiltshire and
GEORGE EDMUND BECKETT formerly of 29 Andrews Street Leicester in the
County of Leicestershire but now of 79 Oxford Street Manchester in the County
of Lancashire, Electrician 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 relates to certain improvements in electric telephone switches
or systems & more particularly to that class of telephones used in warehouses
factories & other places where a number of rooms or stations are situate close
together. The invention relates to certain improvements or modifications of the
system described in the British Letters Patent No. 13,367 of the year 1891 which
Patent was granted to Thomas Sloper & dated August 7th 1891.
A line wie is used for each station, in addition to the earth or return wire
& each line wire is connected to a stud on the switch of the instrument at each
station.
In the case of the instrument to which the line belongs (which line we will call
the home line) the line is not connected to the switch as the others but is
connected through a Morse key (which key we will call B) to the telephone.

page_text: Between the Morse key & the telephone a branch line is connected to one terminal
of the call bell.
The usual switch hook upon which the receiver is hung when not in use is
employed & this is connected permanently to the earth or return line. When
the receiver is hung up this switch hook makes contact with a spring or
equivalent device which is in metallic connection with the second terminal of the
call bell.
The switch hook also makes or breaks the circuit of the microphone & primary
coil in the usual manner where such are employed. Attached to the switch hook
but permanently insulated from it, is a strip of metal. When the receiver is
taken off its hook this strip of metal makes contact with & electrically connects
two separate metallic springs. One of these springs is permanently connected to
the telephone receiver (through the secondary of the induction coil where one is
used) & the other spring is connected to the switch or other device for connecting
to the line wires of the other stations.
Between the latter spring & the switch is a press button or Morse key which we
will call A key. When this key is pressed it comes in contact with a stud which is
connected to the battery & a current is sent through the switch to the line &
instrument of which other station the switch is at the time connected to.
Any suitable form of switch may be employed, but for convenience we prefer to
use a metal arm pivoted at one end & so arranged that the other end is free to be
turned round & so to be brought into contact with any one of the studs connected
with the lines of the other stations.
In addition to these studs in connection with the line wires we sometimes use one
other stud on each instrument. These studs are marked "reply
and are all
connected together by a special line wire which we call the "reply wire."
A wire connects the reply stud on each instrument to the bottom contact of the
above mentioned Morse key B. and the arrangement is such that when the key B
is pressed in the home line is disconnected & the connections joining the Morse key
from the telephone & the call bell respectively are transferred to the reply line from
the home line.
The invention may be more clearly understood by reference to the accompanying
drawing in which A is the ringing stud or key. B is the stud which is pressed in
by the calling station until he receives a reply & has informed the other station of
his number.
C is the line appertaining to the station called the home line.
D is the stud of the switch which is in connection with the special "reply line."
(When no separate reply line is employed in a system this stud is then connected to
the earth or return line.)
E is the switch hook. F and G are two springs which are brought into
metallic connection with each other (but not with the switch hook) when the
receiver is unhooked.
H. is a strip of metal attached to an insulating strip J carried by the switch
hook.
Kis the receiver & L is the spring or contact which.connects the bell to the earth
or return wire when the receiver is hung up.
M is the call bell & O is the switch for connecting to any one of the line wires
appertaining to the other stations.
P is the terminal in connection with the earth or return wire & Q is in connection
with the battery R.
When a microphone is used the connections are as those usually employed in such
cases, but we prefer to use a separate cell (or cells) for each microphone & to keep
the microphone circuit out of metallic connection with the earth or return wire.
It will be understood that a magneto may be employed for calling purposes if
desired.
We do not confine ourselves to any particular method or arrangement for making
or breaking the connections of the switch hook or studs as the same or similar

page_text: effects may be attained by other arrangements than the examples shown in the
drawing.
The working of the instrument is as follows-Suppose a person at No. 5
instrument wishes to communicate with No. 3 he first puts his switch on No. 3 stud
& presses the key A which sends a current to No. 3 station. This current arriving
through the home line at No. 3 station passes through the Morse key to the call
bell and to the earth (or return line) through the switch hook.
In addition to pressing his key A the person at the calling station presses his
key B. until he hears his own bell ring & has informed the person at the called
station of the number of his station.
The person at the called station upon hearing his bell ring places his switch on
the stud marked "reply" & presses his key A which rings the bell at the calling
station.
He then listens at his receiver until he is informed the number of the calling
station when he places his switch to that number & the connections are
complete.
Conversation can then be carried on without any possibility of cross talk occuring
with other stations on the system.
In order that the "called" station shall not press is key B in mistake we
so arrange that when the switch is at "reply" this key cannot be used.
If no reply ring is required the special reply line may be omitted & the reply
stud connected to the terminal of the ordinary return or earth line.
In this case the operation is the same except that the person at the calling station
listens at his receiver instead of waiting until his bell rings.
"
It will be understood that the ringing current from the calling station goes
through the home line of the "called "
station & returns through the earth or return
wire.
When the extra "reply line" is used the speaking is first through the home line
of the "called station' returning by the "reply line" until the called station
knows what station is calling, & it is then through the home lines of the two
speaking stations the earth or common return lines being cut off.
Having now particularly described & ascertained the nature of our said inven-
tion & in what manner the same is to be performed we declare that what we
claim is―
1. The combination & arrangement of parts forming the complete telephone
instrument substantially as described & illustrated in the accompanying drawings.
2. In a telephone instrument such as described a movable contact such as B
which in its normal condition connects both the telephone and the bell with the
home line & which when operated disconnects the home line & connects to a special
reply line substantially as described.
3. In a telephone instrument of the class described a movable contact such as B
which in its normal condition connects both the telephone & the bell with the home
dine & which when operated disconnects the home line & connects to the earth or
return line substantially as described.
4. In a telephone instrument of the class described a switch hook such as E
connected with the earth or return line & arranged in such a manner as to connect
the switch with the telephone without electrically connecting itself with either when
the receiver is off its hook.
5. A telephone instrument of the class described in which the home line is
connected to both the telephone & the call bell & so arranged that the bell is
connected to the return wire when the receiver is hung up & the telephone is con-
nected to the switch when the receiver is removed in combination with a stud or its
equivalent such as B for disconnecting the home line and temporally connecting the
reply line (or the common return) substantially as described.
6. A telephone system having separate lines appertaining to each station a return
or earth line and a special reply line the whole being so arranged that the reply

page_text: line may be temporally used for conversation between any two stations & that a
circuit may be afterwards formed through the two lines appertaining to the two
speaking stations substantially as described.
Dated this 20th day of February 1896
THOMAS SLOPER.
GEORGE E. BECKETT.