The automatic telephone switchboard was introduced in 1892 along with dial telephones. The students refused to allow telephone calls go through the telephone switchboard. Originally, telephone exchanges consisted of manual boards operated by switchboard operators. Thames's telephone switchboard was jammed by complaining viewers. Point to point video calling required swapping connections on a telephone switchboard. The main office features a functioning manual telephone switchboard that is still in use. The Avalon telephone directory in 1920 listed 52 subscribers serviced by a manual switchboard. The sentence was for illegal possession of two facsimile machines and a telephone switchboard. Consequently, the field telephone was designed; a device that operated with its own switchboard. This included weapons, ammunition and a telephone switchboard from the armory. It was originally equipped with 375 telephones and a master switchboard. Later exchanges consisted of one to several hundred plug boards staffed by switchboard operators. The Wang DVX was one of the first integrated switchboard and voicemail systems. Originally, no phone calls could be made without first talking to the Switchboard operator. The first call to the emergency services' switchboard was logged at 12.26 a.m.