A new small crossbar telephone system for private branch exchanges
H. H. Abbott · Transactions of the American Institute of Electrical Engineers Part I Communication and Electronics · 1959
A new small crossbar telephone system called the 756A private branch exchange (PBX) was recently developed for business establishments requiring no more than 60 lines to PBX telephone stations and ten trunks to a telephone central office. Distinguishing features of this new PBX are the small size and attractive appearance of the cabinets for the PBX attendants and the switching equipment. These cabinets have colors and finishes that blend with modern office decor so they can be located satisfactorily adjacent to office furniture.