57 Calling Base.....Radiotelephone Subscriber Equip 70's

In the "old" days of early commercial radio services provided by PMG/Telstra - all radio equipment was located at an exchange and lines taken to subscribers who could connect to the radio system.

Early systems were quite similar in concept to a "party line" radio network.

Each user with one of these handsets would not hear anything in normal use, call monitoring was enabled by reversing the telephone line polarity - this would enable the instrument to "hear" what was happening and to make calls to mobiles.

Typically the mobile user would call his base using a standard two way radio and then wait for the base to respond - the telephone exchange equipment (radio transceivers/signalling control) would talk to the subscriber equipment which would alert the base that a call was being made (light - speaker is enabled at the base)

This gear was used WAY BEFORE the days of trunked or APCO P25 type digital systems.

A crude radio system by todays standard but wizz bang for the 70's

This instrument is only useful as a display item from the past, no practical use these days.

A wonderful curio from the early days of Telco supplied radio communications.

Communico Subscriber Remote Handset

Series 250

Based on a highly modified series 800 type phone (case anyway)

Brown/Green coloured case and handset

This instrument uses a basic home use style telephone case which has been modified extensively, amongst the most noticable changes:

Handset has a dynamic insert on both the RX and TX.

Small chrome button on the handset for PTT

Dial mechanism has been removed, a small speaker is fitted instead.

Lamp fitted on the left-hand side front of the case

Volume control on the right-hand side front of the case

All "normal" components have been removed from the phone - no induction coils, no bell, no capacitor etc.

This telephone was designed to be plugged into another piece of Communico equipment, the linecord is terminated with a custom 5 pin male connector.