This series was updated from the 300 series by the Australian Post Office. It was introduced in 1958. It was based on the British GEC 1000 series, which was in turn based on a 1947 Ericsson design. Attention was given to making it work satisfactorily on long rural lines and light cable. It could work on lines of up to 1000 ohms. It featured a new STC rocking armature receiver, a better anti-sidetone circuit, and a more comfortable rounded handset without the familiar mouthpiece cup of the earlier series. From the start it was designed for Auto, CB and Magneto versions in table or wall configuration. In view of the fading problems experienced with coloured phones, the 400 was only produced in black and Ivory. The ivory color was only available in desk phones, and was only produced by Ericssons. Even so, it still went a dirty yellowish color in strong sunlight.
Although the initial Engineering Instruction showed the phone in a more rounded Ericsson style case as shown at left, production models retained the old 300 style case. Only the handset design was changed.
It was produced by Ericsson and GEC in Britain and AWA in Australia, and there were minor internal differences. The British versions used an internal chassis, but the Australian version had all its components mounted directly on the baseplate. The wall models were only made by AWA.
400 ATH Ivory
400MTH External and Internal views.
Portable model. Note the wire carry handle in the cradle.
An example of the versatility of the 400. This phone was used to control a radio telephone on Solitary Island lighthouse off the New South Wales coast.
The 400 wall phones retained the fold-down front of the 300 series.