IBM 1750, 2750 and 3750 Switching Systems

rdf:langString IBM 1750, 2750 and 3750 Switching Systems

rdf:langString The IBM 1750, 2750 and 3750 Switching Systems were telephone exchange systems produced by IBM from the 1960s to the 1990s. IBM engineers in the IBM La Gaude Research Laboratory, north-west of Nice in France, developed an electronic Private Automatic Branch Exchange: the first stored-program-controlled PABX to be marketed and installed in the world. The product family handled up to 2516 extensions and 356 trunk lines. They were among those very few IBM products to be still in use in five European countries for some 40 years following the 1969 market introduction of the IBM 2750 Switching System. Before 1969 only electromechanical Strowger and Crossbar PABXs were available. The family of IBM 1750, 2750 and 3750 Switching Systems was developed from the IBM 1800. Each system included twin stored-program controllers (each with 32K or 64K main storage}; some 600,000 lines of code; emergency and every-night automatic switchover; twin disks (none for the 2750); and solid-state switching. Extension, trunk and tie lines were connected by discrete transistors on plug-in panels. All systems were assembled in IBM's French Montpellier factory for France, Germany, Italy, and the UK.