|Melbourne Museum of Printing||
Intercom Units [Inter-Office Communications]
In many businesses, `outside' telephones were few. There might be just one line and one phone or very few extensions.
Communications from the factory floor, warehouse, etc would only be to the office. It would have been expensive to have the telephone company provide a switchboard to service all these areas; and the management would usually make it difficult for workers to make or receive phone calls.
One result was that office workers and managers had two telephones on their desk: the `outside' phone and the intercom.
Intercom systems were many and varied and sometimes quite sophisticated, with dial phones identical to the `outside' phones and connected to their own private automatic exchange.
Other systems were much simpler, with point-to-point loudspeaking units, say from office to factory.