The Telegraph and Telephone Journal, March, 1931, page 130:
GREAT BRITAIN.--Broadcast Exchanges.--In the suburb of Bowes Park, London, the first exchange of this kind in the northern part of the great capital was opened early last month with 250 subscribers.
HUNGARY.--This little country has perhaps the largest exchange of this type in Europe of no less than 9,000 subscribers to the wired broadcasting system of what is known as the Telefon Hirmondo. By the way, in addition to this number of licenses, no less than 200,000 were added between Jan 1, 1929 and December, 1930. As we learn from World Radio, this is despite the fact that there are reception difficulties in some parts of Hungary, while it is easier to receive from certain foreign stations than from the home station. It is, however, expected that two new relays of 10 kw. will be opened toward the end of the present year, one in western, and one in north-eastern Hungary.