A telephone switchboard was a device used to connect circuits of telephones to establish telephone calls between users or other switchboards, throughout the 20th century. The switchboard was an essential component of a manual telephone exchange, and was operated by switchboard operators who used electrical cords or switches to establish the connections. The electromechanical automatic telephone exchange, invented by Almon Strowger in 1888, gradually replaced manual switchboards in central telephone exchanges around the world. In 1919, the Bell System in Canada also adopted automatic switching as its future technology, after years of reliance on manual systems. Nevertheless, many manual branch exchanges remained operational into the second half of the 20th century in many enterprises. Later electronic devices and computer technology gave the operator access to an abundance of features. A private branch exchange (PBX) in a business usually has an attendant console, or an auto-attendant function, which bypasses the operator. Following the invention of the telephone in 1876, the first telephones were rented in pairs which were limited to conversation between the parties operating those two instruments. The use of a central exchange was soon found to be even more advantageous than in telegraphy. In May 1877, The Holmes Burglar Alarm Company in Boston, Massachusetts, established by Edwin T. Holmes installed the first central office and switchboard that served both as a security service at night for banks and businesses, as well as a telephone system. The switchboard operated telephone instruments manufactured by Charles Williams, a licensee of the Alexander Graham Bell company. In January 1878 the Boston Telephone Dispatch company had started hiring boys as telephone operators. Boys had been very successful as telegraphy operators, but their attitude, lack of patience, and behavior was unacceptable for live telephone contact, so the company began hiring women operators instead.