Director switching device, made by the Automatic Telephone Manufacturing Company, Edge Hill, Liverpool, England, 1927. From the first London director exchange at Holborn. With case.

The Director telephone system was used in some large cities in Britain between the 1920s and the 1970s. In large conurbations there were many telephone exchanges and special means were needed to connect any two callers together. Within such areas, a switching device called a director routed telephone calls between exchanges that were not directly connected with each other. A three-letter code identified each exchange. The first director exchange in Europe was opened at Holborn Exchange, London, in 1927.