Australian Public Telephone


Name Long Tom Variable Tariff
Maker GPO
Date 1920s-80s

This coin receptacle features the early type penny coin head, and was kept in service up until the end of two-penny call charges in 1955. It could be attached to any type of telephone, making it a versatile unit for connection to unit fee (local call) type public telephones.

This type of rectangular telephone is one of the early types of unit fee automatic public telephones, which were fairly common during the 1920s. This particular telephone is one that has been modified and features a modern hand piece and a ten-cent coin head.

This type of public telephone dates back to the late 1920s/early 1930s, and was modified many times by the PMG workshops, enabling its use to be maintained over a long period of time. The telephone shown here has been modified to accept four pennies on a ramp type coin head. Note that this phone still has the fixed transmitter on the front of the metal case, and features a 'bell' type receiver. Later modifications to this type of telephone included the molded Bakelite hand piece.

NswA.jpg (58048 bytes)

Sydney Workshop Long Tom  This phone appears on page 64 of Jim Batemans book.  The phones I have seen have been painted with grey hammertone type paint.  The door with the dial swings open to reveal the coin mechanism.  The Sydney workshop version was a reinforced phone designed to withstand atempts at coin theft.
Coins are placed in the top where they roll down a chute to the coin mechanism.   There is no coin refund chute.

Henry Titchen

Variable Tariff





An installation peculiarity was that particular attention was necessary on instal�lation to ensure that the mounting was rigid and that the springs were correctly adjusted so that well aimed blows on the side of the case did not generate false deposit signals.

The system of pre-payment on answer continued until about 1935 when an explicitly designed public telephone to take advantage of the changes in the operation of ex�changes was introduced. The coin receptacles had worked well on city manual or central battery exchanges or on country manual and magneto exchanges, but were not suitable for semi automatic and automatic exchanges, which had been progressively introduced through the late 1920's and early 1930's.

AUTOMATIC FIXED UNIT FEE OPERATION: By the late 1920's the momentum of establishing automatic exchanges had necessitated the design of a local call telephone which did not require operator assistance. What occurred was the adoption of a universal design which incorporated a coin receptacle, very much like the original shapes, with a housing at the top containing the circuitry. This top compartment was fitted with a switch hook and bell receiver, dial and transmitter being fixed into the face of the compartment door, which opened for easy maintenance. The bottom coin compartment which held a removable coin tin also aped the shapes of the earlier coin receptacles. Fig.6 depicts the oblong as opposed to the round version, and Fig.7 illustrates the automatic fixed unit fee mechanism.

HOW THE MECHANISM WORKED: When a line potential reversal was received on 'called subscriber answer', a polarised relay operated preventing conversation until the user inserted two pennies. These ran halfway down the coinway where they were held by a roller and spring which operated to short circuit the relay, allowing conversation to proceed. When the receiver was restored the switch hook mechanically released the roller which allowed the pennies into the coin tin.




The two penny coin head and layout of the mechanism could not be adapted to accept a change in tariff, it was restricted to one or two penny operation.

AUTOMATIC FIXED UNIT FEE OPERATION (BARREL TYPE): A variation of the type depicted in Figs. 6 and 7 above was the barrel version which had the same mechanism, but varied in outward appearance, having a round coin receptacle. This type was intro�duced in the 1920's during the days of two-pence operation and was adapted through the years in a variety of ways which will be discussed later, eventually being withdrawn finally in the late 197U's in conjunction with the Coin Telephone No.3

In their original form they looked and worked as in Fig.7 and later as 11 and 12 with straight coin chute to overcome problems in jamming. The is generally known as the Variable Tariff instrument, but this term to a phase of its life when it was fitted with an adjustable penny  which allowed for tariff changes without serious changes to the mechanism or coin head.



It is generally accepted that the long breech was used in public telephone cabinets whilst the short breech was primarily used in restricted locations such as institut�ions, factories and residential flat buildings, usually as leased services.

Figs.B and 9

As already mentioned the instrument above was-to undergo several basic changes; the above two penny mechanism and coin head was replaced in 1955 by the four penny Variable Tariff coin head and multiple penny mechanism, followed by the six penny coin head

and revised mechanism in 1964, and the new coin head in 1966, and the ten cent revision in 1975, with progressive conversion to handset operation.

The instruments depicted in Figs. 6 and 8 were painted dark green and as in Fig.B featured solid back transmitters. The insert type of transmitter as in Fig. 6 is a later modification. The bell receivers were PMG pattern with rubber grumet to ease wear on the cord, and they were in the above period generally painted dark green.



BARREL CARCASE WITH ASSOCIATED HANDSET: IF addition to the fixed transmitter and bell receiver varieties, another well known variation in use in major pay stations was that which utilised a 'barrel' carcase with blank door, in association with a table telephone. Although this variation - was used as early as the 1930's it was not until the early 1960's when bell receivers and solid back transmitters were in short supply, that these combinations were used in quantity. Earliest examples used a 'pyramid' 162 type table set (Fige11) progressing through the introduction of 300, 400 and 800 table sets,

Fig. 11


AUTOMATIC ELECTRIC TYPE: An early Sydney workshop type introduced for use around Sydney in the late 1920's was the distinctively Automatic Electric instrument (Fig.13) This public telephone was designed by local engineers to overcome the operational shortcomings of earlier manual types and take advantage of the improved facilities offered by the newly provided automatic exchanges. Some of the advantages listed for the introduction of this type:�

a) Prevented use of bent or misshapen cains(washers).

b) Allowed coin to be inserted prior to connection and connection was auto�matically made by pressing a button marked 'service'.

c) The instrument had provision far coin return which earlier instruments lacked.

This type was however, quickly abandoned probably due to heavy maintenance, and per�haps, because the concept was too advanced for the existing exchange network of the time. The mechanism was different to that already described and because it was little more than an experiment will not be described here. Note the penny coin head which was also widely used on other one penny coin collectors.

Fig. 13



Fig. 14                                                                                         Fiq.15

VARIABLE TARIFF LOCAL CALL INSTRUMENT: In 1955 a new mechanism was introduced to all existing Automatic Fixed Unit Fee instruments. The mechanism was so that it all attached to a backing plate which could be completely removed for maintenance, unlike the earlier two penny type which had parts strapped to areas of the interior. The new redesigned coin head had provision for up to 4 pennies to allow for tariff changes (Fig.14). The coin head was slotted to allow three or four pennies and a button at the end of this slot, when pressed, the coins to run down in sequence.

VARIABLE TARIFF MECHANISM WORKED: The coins passed straight through the coinhead �to the tin, but in so doing each successive coin triggered a pawl which acted  escapement. As each coin passed the pawl, the escapement dropped one

The correct number of coins caused the escapement to operate springs which the circuitry to allow conversation to proceed.



Left Fig. 16 Right Fig.17

1964 AUTOMATIC FIXED UNIT FEE INSTRUMENT REVISION: The existing Variable Tariff inst�ruments were modified again in 1964 to allow for a six penny local call rate. A new coin head of the fixed insert type was provided and the penny chute was replaced by a narrower chute track, and the number of teeth on the escapement reduced to one.

Left Fig.18 Right Fig.19 Magneto Barrel of the type phased out in 1960.


LOCAL CALL BARREL MAGNETO VERSION: As the unit fee tariff increased in country manual areas the fixed transmitter type barrel changed in the same ways described for auto areas; the change of coin head and mechanism was the same. Basically the barrel type had a magneto where the dial is situated on conventional instruments. Even CT1 instruments were designed at a much later date for manual areas.

1966 LOCAL CALL BARREL REVISION: Decimalisation in 1966 meant that the existing coin head had to be changed to five cents. Both five cents and six pence are the same size so there was no change to the mechanism, but because both currencies were cir�culatino, a redesigned coin head was provide[]. A five cents or six pence coin head of the roll coin design was provided on all existing barrel instruments.

1975 LOCAL CALL BARREL REVISION: ihe !OF-al call fee was raised to ten cents in 1975, necessitating the changing of coin chute and a new roll design coin head. The type of instrument this applied to are t-ose depicted in Fiy. 23, and this was the final change to the barrel. type instrumer-t~ =efore they were replaced.


VARIABLE TARIFF HANDSET CONVERSION: The early 1960's saw a shortage in the avail�ability of bell receivers and fixed transmitters, and a new type of Variable Tariff instrument was adapted to replace the former transmitter and receiver type, with a combined 300 type handset. The bell receiver fork was replaced with a moulded one able to accept a handset, and the hole where the transmitter had been fitted into the face of the mechanism compartment was 'blanked'. Also, the circuit was improved

using an anti side tone induction coil and by dispensing with fixed transmitters which had inherent problems of their own.

Above Fig.23 (transmitter blanked) Left Fig.23(a) (no transmitter hole) Right Fig.24

(Sydney Workshop Model)

REINFORCED SYDNEY WORKSHOP TYPE: The basic long and short barrel PT's remained the same in appearance (Fig.23) the only modification being reinforcement to overcome heavy vandalism following silver coin conversion. They Sydney Workshop type with dif�ferent lock and reinforced steel front is depicted in Fig.24. Instead of the pressed metal door of the older version, it has a reinforced steel plate with an unconventional locking pattern. Earlier instruments were dark green with traditional enamel dial plate, while the later model was metallic grey without the dial plate. Both of these models were handset operated. Coins were again placed on the coin-head ready to roll down the chute when connection was made, and no refund facility was provided. As with the earliest UT's details of 'lost coins' were reported to the operator who arranged for a refund to be sent out by mail.


History of the Telephone in New South Wales, Jim Bateman, 1980
ISBN 0 95944787 0 1