English: Automatic Telephone Exchange- Communications in Wartime, London, England, UK, 1945
Engineering officers and test clerks at work at the test desk at an automatic telephone exchange in London. According to the original caption, this is where "engineering officers deal with the public on faults and service difficulties. The test clerks can reach any required line by dialling and test the exchange equipment and then the subscriber's circuit. They can remain in circuit while the subscriber dials and observe the point at which a fault condition occurs".