PAYPHONE

The caller then pushed Button A to deposit the coins and make the connection. If a call could not be connected for some reason, or if there was no reply, Button B was pushed and all the coins were returned.

MULTI COIN PUBLIC TELEPHONE ATTACHMENTS: In the 1930's the PMG adopted a multi coin attachment which had been developed by the British Post Office, (manufactured by Hall Telephone Accessories Ltd) to allow the public to make trunk or local calls from the same instrument. It should be remembered that by this time public telephones were being provided at an increasing rate, and at unattended locations, that is to say away from Post Offices where toll calls could be arranged. The new attachment could accept three denominations of coin, penny, six pence, and shilling, which en­abled local or trunk calls to be made with operator assistance from common battery and magneto exchanges, and allowing automatic local calls and operator assisted calls from automatic exchanges.

For local calls, the user inserted the coins which latched a weighted balance armand on answer operation of an 'A' button deposited the coins and allowed conversation to proceed. 0n ineffective calls the money was refunded by operation of button 'B'. This operation also triggered a buzzer which acted as a warning to operators of button mis-operation during trunk line calls.

During trunk calls audible identifying signals were forwarded to the operator; a tone from a spiral gong when one penny was inserted, tone from a bell being struck once when a sixpence was inserted and tones from the bell being struck twice when a shil­ling was inserted. When the operator was satisfied with correct coin insertion, the user was asked to press button 'A' to allow deposit of the coins and allow conversa­tion to proceed.

Prior to 1964, the unit fee change from 2d to 3d and then to 4d was accommodated by moving the weight of the balance arm to a position where it would latch with the required number of coins. During the 4d era, an additional latch was fitted to the back of the mechanism to allow the use of a sixpence for local calls for any user who was not carrying four pennies.

When the change of unit fee to 6d took place in 1964, it was not possible to adjust the arm to operate with six pennies and the mechanism was redesigned to operate with a sixpence for local calls. The penny runway was redesigned to accept a two shilling piece in lieu of pennies and the one shilling runway was retained. To ensure correct operation with the lightweight sixpence, the balance arm was redesigned to latch with a magnet and restoration was achieved by a special arc fitted to the coin quadrant which was activated during 'A' button operation.

COIN HEAD CHANGES: The coin head underwent a change from accepting one penny, sixpence and one shilling, to sixpence, one shilling and two shillings, thence to decimalisa­tion, five cents, ten cents and twenty cents. The instruments used in association with the multi coin attachments were those used for normal subscriber use and were small wall sets such as Stromberg Carlson (Fig.27), Automatic Electric, and the standard PMG 127 of whatever make (Fig.1).

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PUBLIC TELEPHONES:                                                                                              PART FOUR

ONE BUTTON ATTACHMENT: This type was imported for use in magneto areas and was also known as the 'post payment' type as opposed to the 'pre payment' two button standard type. Only a few were ever used in N.S.W. and these were quickly abandoned in favour of modified two button types.

In this type the 'A' button was replaced by an ac relay operated by ringing current from the exchange. The depositing of the coins is under the control of the telephon­ist who operates a special ringing key. A Cailho circuit is required for the operat­ion of the depositing relay. This requirement led to the abandonment of the one but­ton type of attachment as it was necessary, in order to provide continuous service, to night switch the public telephone to a distant continuously staffed exchange via a minor trunk line. In many cases where the installation of a multi coin attachment was justified it was found that a Cailho circuit could not be made available and the pro­posals had to be abandoned or deferred.

STD ATTACHMENT: With the introduction of subscriber trunk dialling which enabled direct dialling of trunk calls without operator assistance, some two button multi coin attachments were modified to accept only 20c coins. These attachments were en­amelled orange to distinguish them from conventional black attachments. Of course the coin heads were modified to accept 20c coins only. In N.S.W.the use of these public telephones was confined to the popular northern coastal resorts.

NUMBERS: At the peak of its usage the multi coin attachments in use exceeded 20,000 Australia wide, and of these only 400 were STD versions. The two button attachment was the standard trunk line instrument until the introduction of the Coin Telephone No.1 in 1966, and with several modifications to accept changing denominations, to 10c at present, is only being phased out of use.

Fig.27