A LARGE and imposing building called Telephone House has been built in Birmingham to accommodate the telephone equipment for the city and also the Post Office and engineering and administrative staffs. A description of the telephone equipment required for the trunk, toll and central exchanges which were installed by Siemens Brothers and Co., Ltd., of Woolwich, to the order of the Post Office, is given in the September supplement of the Siemens Magazine. The introduction of the maximum fee of one shilling for three minutes on all inland trunk calls made after 7 o'clock in the evening has made the trunk service very popular, and the more recent introduction of a half-crown maximum for a three minute trunk call between any two places on the mainland of Great Britain will still further increase the amount of trunk traffic. Outside London, Birmingham is the most important telephone centre in Great Britain. It is connected by direct trunk lines with all other zone centres and, in addition, forms an important link in the alternative trunk routes between London and other zone centres such as Liverpool, Manchester, Leeds, Sheffield, Nottingham and Leicester. The new trunk and toll equipment has been planned to meet the long distance (trunk) and the short distance (toll) traffic anticipated in the Birmingham district during the next few years. Since 1930 the development of the trunk traffic has exceeded all expectations. There have been installed in the building 367 switchboards, and in addition a centralized manual board for the whole of the Birmingham area. In the same building also a 5,700 line full automatic equipment for the central exchange is being installed. Two motor generator sets driven from the 400 volt 3 phase 50 cycle public supply mains, with an output of 1,600 amperes at 57 volts, are being used.