In 1882 the Gower-Bell telephone became the GPO's standard set with 20,000 sets ordered. There were two types of Gower-Bell instruments used by the British Post Office. The first pattern used tubes for receiving speech (although some were later retrofitted with Bell receivers) and the second pattern which had a smaller case and only used Bell receivers for speech reception.
The telephone wiring was on the rear of the instrument and consisted of un-insulated wire, stapled to the wood.
The first pattern Gower-Bell telephone remained the Post Office choice for many years, and was continuously developed. By 1886 it had become known as the Universal Telephone, so-called because it could be adapted for use under practically any conditions likely to be met with in Post Office service.
It is probable that the speaking tubes on some telephones were replaced after the Bell patents had expired (1891). The telephone still retained the Gower Transmitter, with mouthpiece, but the receiver and speaking tubes had given way to a pair of Bell receivers.
The Gower-Bell company called the instrument the "Gower-Bell Loud-speaking Telephone".
Gower-Bell telephones were supplied worldwide, but all the Gower-Bell telephones produced for the GPO were clearly marked on the front of the case with an enamel plate.
The Gower-Bell telephone superseded the Crossley (Made by Blakey and Emmott) which was the Post Offices first telephone.
These telephones were used on permanent current system exchanges.
This telephone, made by the Gower-Bell company, used a rather large receiver mechanism, which was invented by Frederick Gower. It consisted of a very large magnet which made it more powerful than other makes, but was too heavy to be held to the ear. Because of this it was fitted inside the wall cabinet and connected to two listening tubes.
A thin membrane covered the transmitter and this itself was sometimes covered with a wooden sheet that had slots and carvings in it to allow the sound through.
An induction coil with resistances of 0.5ohms (primary) and secondary of 250ohms (secondary) was fitted.
There are two automatic prong hook switches, on each side of the telephone, in which the ear-pieces of the flexible tubes are placed when not in use. The right-hand one serves to break the local microphone circuit, the left-hand lever is the usual bell and telephone automatic.
At the top of the telephone is a press button for calling the exchange.
The incoming calling signal was a trembler bell which was rung by a battery at the subscriber's premises under the control of a relay operated by a signalling current received from the exchange. The relay was fitted inside the telephone. A feature of this system of working which has a modern sound was that when an operator rang the subscriber's bell she could hear the interruption in current caused by the trembler bell contact, a forerunner of ringing tone. The relay resistance would be 100ohms.
One key disadvantage when using this telephone was that the design of the instrument required the user to remove and hold both tubes while speaking. This also operated the automatic hook switches which signalled the exchange, thus leaving no hands free for writing.
There were a number of changes made to the phone and this is self evident by changes to the circuits and terminal layout. On some telephones the labels were marked: BC, ZE, L and C, the six terminal model was marked BC, L, Z, ZC, Bell and Bell, whilst the eight terminal model was marked 1 to 8.
The telephone also changed when the transmitter cover was replaced with a thicker wooden plate, which had a white coloured Porcelain mouthpiece fixed in the centre. This helped concentrate speech onto the transmitter mechanism fitted underneath. The Consolidated Telephone Company made many like this.
Some later telephones were retrofitted with a Hunnings type transmitter.
The white labels fitted by the terminals were made of Ivorine.
Many early telephones were privately bought and connected between buildings, up to 14 miles apart (see advert).
In the original Patent, the line is shown as a single wire with an earth return, which was the normal way to connect at the time. But due to induction from the multitude of overhead wires at the time, telephones using an earth return were extremely noisy. The GPO diagrams only show two wire connectivity and this was the best way to stop induction at the time.
First Pattern Circuit Arrangements
Original Type and Six Terminal Type
Two cells must be used for speaking and two for local circuits.
Current required for Relays, 16 milliamperes.
Separate Bells or Relays are in all cases to be treated as separate Instruments.
The notes above are general for all the arragements
mentioned below but excluding the eight terminal type.
Ordinary Type (with 4 terminals)
Ordinary with Bell
This telephone has a four Terminals, a Relay and an integral Bell.
Note the 4 terminals and the bell gong
The transmitter is located under the black plate
Internal view - the press button has been removed
There is a relay these telephones and the bell mechanism has been removed, so an external bell would have been supplied.
Old Form, six terminal telephone (Internal view)
New Form, six terminal telephone (External view)
New Form, six terminal telephone (Internal view)
Old Form with Relay
New Form in Simple arrangement
New Form with Relay
New Form for Exchange working
Between ZE and C are connected the two Leclanche cells required for the microphone. Between EC and ZE five Daniell cells. When the left-hand lever is down this battery is permanently connected to line. This constitutes the peculiarity of the system, as it is worked on the closed circuit system, a battery current always passing through the line when the instrument is not in use. No earth return was used on this instrument, with double or metallic circuits being almost exclusively employed, and these were absolutely necessary, owing to the fact that the lines are run in close proximity to single-wire telegraph circuits, the induction from which on single-wire telephone lines rendered the voice nearly or quite inaudible.
Eight Terminal type
No alteration of internal connections was required, but when a Relay was placed in the telephone case the coil ends would have been connected to the two right-hand screw studs, the base-plate to the fourth screw-stud (counting from the left), to which one end of the Receiver coils was also connected, and the contact block to the disconnected wire. When a Relay is not used the two right-hand screw studs would to be connected together by a wire.
Leclanche Batteries (Porous-pot form) were used, unless the circuit was exceptionally long and underground, or is very busy. In such cases authority would have been obtained to use 6-block Agglomerate Leclanche Batteries for speaking.
Two cells were used for speaking and two for local circuits.
Current required for Relays, 16
Separate Bells or Relays were in all cases treated as separate Instruments.
The telephone is fitted with six internal terminals and eight terminals, at the bottom of the backboard, which are numbered 1 to 8, from left to right.
The notes above are general for all the situations mentioned below.
8 terminal type with Gower Receiver
8 terminal type, retrofitted with Bell Receivers
In the circuit diagrams below the component locations are:-
The Bell is separate from the Telephone.
For Exchange Working
The Relay was adjusted with a "bias" sufficient to prevent it responding to the permanent current from the 5 cell Daniell Battery. A resistance would be inserted in the relay circuit to reduce the permanent current to between 18mA and 20mA.
Telephone at Intermediate Office
All the information above was taken GPO Telegraph Apparatus Connections and Circuits instruction (Dated 1886).
Second Pattern Circuit Arrangements
The second pattern was considerably smaller than the first pattern, measuring 7 inches by 5 inches and projecting 6 inches. The diaphragm is stained black. The great objection to the china mouth-piece arrangement, used on the 1st pattern, lies in the fact that moisture is condensed upon it and when the telephone is much used most unpleasant odours are present. So the china mouthpiece was removed and the telephone reverted back to it's original look. The fixing heads for the transmitter were deliberately left showing on the transmitter tablet in an attempt to stop users from using the plate as a surface to write upon.
Second pattern Gower-Bell telephone
made by the
The internal connections of the Post Office telephone are shown at the bottom of this page. The transmitter is connected to two flanges upon the inside of the case. A screw passes through the flange on either side; thus joining the microphone to the connections on the back board of the instrument.
In this instrument the two Bell receivers are shown joined up in parallel. The induction coil is fitted beneath the case, and formerly had a resistance of 0.5ohms and 150ohms respectively for primary and secondary. A coil having from 0.9ohms to 1.2ohms and 25ohms is now used (Coil, Induction No.1). The instrument is fitted with eight external terminals, which precisely correspond with the eight terminals fitted to the first pattern Gower-Bell telephone. The two central terminals are connected to the lines. From terminal 4 the current passes to the end of the lever button, along it to the left switch lever through the upper contact to terminal 1; from terminal 5 to the centre of the right switch lever, through the upper contact to 3. Thus the bell must be joined between 1 and 3. When the receivers are raised the left switch-arm joins them up, and the right switch-arm joins up the microphone battery, which is connected between 5 and 6. Terminal 7 is used for the ringing battery, which is joined up in series with the micro-phone battery, which is joined up in series with the microphone battery, which unites with it.
It will be seen on the circuit diagram that two terminals are joined together by
a dotted line and they are marked "relay." Where a relay is not used these
terminals connected together by means of a wire link, but when a relay is
used this wire is removed, and the relay coil connected between them. The contacts of the
relay are joined to the two wires marked "local."
Second pattern circuit diagram (Single receiver)
Second pattern circuit diagram (Double receiver)
All information on the second pattern telephone was taken
from "The telephone system of the British Post Office, a practical handbook"
by T.E. Herbert, dated 1901.
The copper strips c c are connected by wires to two substantial pieces ofbrass, B, of which one only is shown in Fig. 1. When the cover is placed in position on the base A A (Fig. 2), these blocks are screwed tightly to the angle-shaped pieces of brass b b, making good electrical contact. The other apparatus shown on the board consists of the levers L1 L2, for hanging up the receivers when not in use. This process of hanging up changes the contacts at the far ends of the levers from C1 to C2, and from C3 to C4, respectively.
The induction coil is at I, and there are eight terminal screws along the lower part of the board, which are left exposed when the cover is screwed down.
When a relay is not fitted a wire link is inserted at position S on fig. 3,
The connections between the various parts are made by wires at the back of the board and are shown diagrammatically in Fig. 3, where the eight terminal screws at the bottom of the board are numbered for reference. The induction coil is represented by thin and thick spirals, and there is a press-button p for ringing-up, not shown in the other figures. The receivers R R are represented as hanging on the levers L1 L2, the cords attached to them consisting of twin wires whose other ends are connected to the screws on the board ; the screws themselves being so cross-connected that the two receivers are in parallel. The various fine straight lines represent the connecting wires, which are insulated from one another where they cross on the diagram.
When used for "simple" working on short lines whose resistance does not exceed 200 ohms, an ordinary trembling bell is attached to terminals 1 and 3, the line wires are attached to 4 and 5, and a split battery of Leclanché cells to 5, 6, and 7. In this case terminals 2 and 8 are not used. A wire is inserted in the position of the dotted line s.
As shown the apparatus is ready to receive a "call."A current coming by the line wire to 4, passes through p to the centre of lever L2, then through spring C4 and the wire s to terminal 1, through the bell back to terminal 3, then through spring C2, lever L1, to terminal 5, and back by the other line wire. The bell is thus rung without the current passing through any other resistances but those of connecting wires and contacts.
The receivers R R being now lifted off the hooks and held to the ears, currentscoming by the. line wires have a totally different course. Arriving at terminal 4 a current passes through p to L2 as before, but now the contact is made with spring C3, instead of spring C4. From C3 the current passes through the fine spiral of the induction coil, through the two receivers in parallel, then to L1, and back to line through terminal 5. The telephonic message is therefore heard in the receivers.
For transmitting, the above circuit is acted on inductively by the primaryspiral of the induction coil, and the induced currents take the path just traced out. The primary spiral is in circuit with the battery and the microphone, which causes the sonorous pulsations in the battery current. The battery current takes the following course:- Starting from terminal 6, it passes through the thick wire spiral of the induction coil to the block B2, thence through the microphone M to the block B1, through spring C1 to L1, and back to the battery by terminal 5. Thus any change of resistance at M alters this current. The requisite changes of resistance are brought about by simply talking near and towards the sloping board (Fig. 1), which carries on its under-side the sixteen microphonic contacts.
It is not necessary or advisable to shout or talk loudly to the board. Clear anddistinct enunciation in an ordinary conversational tone of voice, with the speaker's mouth ten or twelve inches from the board, gives excellent results if the line be in good working order.
The circuit for ringing-up the exchange or the distant correspondent is verysimple. When the button P is pressed, the spring p breaks contact on the left and makes contact with the knob A below. The current of the full battery starting from terminal 7 passes through A and p to terminal 4, away to the distant end and back to the battery by the other line through terminal 5.
We have described the courses of the various currents when the apparatus isused upon a simple telephone line. Without altering the internal connections it can also be used at an exchange or at an intermediate office, or at an ordinary subscriber's office. If necessary a relay can be inserted for ringing-up purposes.
It is therefore applicable to all the usual requirements of ordinary telephonework.
It only remains tobe added that the Bell magneto receivers are of the double-pole pattern, very little modified from the Siemens and Halske's pattern.
Taken from "Electricity in the Service of Man" (dated 1897)
The circuit diagram for the 2nd Pattern, single
receiver, model is the same as the Telephone No. 17 and the 2nd Pattern,
double receiver, model is the same as the Telephone No. 19.
And possibly on the Underground in London
First pattern Gower-Bell telephone with cover removed
The British Science Museum have an instrument made by Scott and Wollaston, England, dated 1880.
Last revised: February 25, 2024