300 Series

The British Post Office 332 bakelite phone was introduced in Australia in 1939. It was largely developed by Ericsson Telephones Ltd in Britain. It reduced the number of mouldings from 10 to 5, giving greater production efficiency. The redesign also did away with the fragile cradle of the 162 and 232, and its somewhat unreliable switch contacts. The new phone was fitted with Ericsson handset cords, which had been found to be resistant to tangling in use. The cords were colour-coded to the later coloured models. All external metal parts were chromed. A magneto model was not intended, but could be made up by adding an external magneto generator in a separate box. The phone was made in phenol formaldehyde, a compound generically called bakelite. It was ideal for thermosetting moulding, was durable and of good insulating qualities, and was designed to fix some of the inadequacies of the 162. The coloured models were made in Imperial Chemical Industries' methylmethacrylate, tradenamed Diakon.

With some experience with the phone, the APO was able to suggest a number of redesigns and modifications. The bell gongs were provided in different thicknesses of steel to give a slightly different and more pleasing tone (parts 2 and 2A). A small Alnico generator used by the APO was reworked to make it easier to turn, and fitted into the front of the case to make a magneto phone, the 333/4. The 164 handset was replaced by the updated 184 model, with the BPO No. 13 Inset transmitter. The note drawer was done away with because of problems with it sticking and breaking, and a blank plate substituted. Initially a wall model was not provided for by Ericssons, but this was added to the range as the phone proved its worth. Except for the dial and cords, the entire phone could be produced in Australia. This was a good move as World War 2 had started and supplies of imported phones would become erratic. At this point the phone was produced in black only. Some green and red phones had been imported before the start of the War, but these purchases were suspended and not resumed, as experience showed that the colored models still suffered from fading. Some of the initial production was fitted with black-finished dials, but the chromed "StayBrite" dial was soon substituted.

332CBTH and 332ATH were the original models. The 333MTH was rare in Australia, but following the modifications suggested by the APO and development of the smaller internal generator, it was produced as the 334MTH.

330MTH was a WW2 Australian expedient telephone , using bells from STC, small generator from GEC, standard 300 case from STC/AWA (now being produced in Australia), and the 164 handset from Siemens. The handset will usually be dated 1940.

312ATH was produced for duplex services. It had a pushbutton mounted in front of the handset and a nameplate reading "Call Exchange".

A similar phone with a pushbutton marked "Ring" was used as an extension phone off a switchboard or intermediate telephone. A version with three pushbuttons marked "Main Extn , Extn Exch, Main Exch" was a replacement for the old Teleintermediate and JS&B intermediate telephones. These phones were issued under Serial/Item numbers, but do not appear to have been given a 300 model number.

The 332 "Tropical" is a GEC phone. It was brought in in small numbers around 1939, probably for evaluation. GEC made many standard design phones for the British and Australian Post Offices, but also produced their own customised models where they thought they could improve on the original. It is marked "PMG 38" underneath.

336CBTH was a CB model fitted with a generator as well. This was used as an extension phone off an extension switch. The magneto was used to signal back to the main station. It was a British Ericsson model N1326K.

The 338MTH is another magneto model. It is a later emergency model produced by TMC using non-standard parts around 1955 - 1960, to keep up supplies of magneto phones while the 800 series was being designed. Its most obvious difference is the smaller bell gongs with one mounted vertically and one horizontally.













L to R: 332ATH Ivory with drawer for writing paper (an optional extra that the APO dropped); 332CBTH with a blanking plate over the dial hole, 334MTH . The H for "handset" was specified because at this time the APO charged a premium for handset phones. This premium was soon dropped as sufficient supplies became available.



This is an extremely rare transparent perspex version built for training and display purposes. A limited production of an Ivory model was also carried out.











The 300AWH version. The right picture shows its fold-down front for servicing. It was also available in a CB wall model that was widely used in Public Telephones, and a magneto model.










The 300 auto table models were *briefly" available in Jade Green, Chinese Red and Ivory as well as black. Extra rental was charged for coloured sets. Because of the fading problem they were eventually dropped from the range. India Telephone Industries produced the phone in other colours and some of these are currently being sold through antique shops.


Courtesy Denys Parker

300AT circuit.










For an article from the Australian Telecommunications Journal (1945), click HERE



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