page_title: IBM 1750, 2750 and 3750 Switching Systems
section_title: Management facilities
hierarchical_section_title: IBM 1750, 2750 and 3750 Switching Systems / Management facilities
caption_attribution_description: English: The IBM 3755 Operator Desk was used with IBM 1750, 2750 and 3750 Switching Systems which were the world's first stored-program-controlled PABXs (Private automatic branch exchanges). They were developed from the late 1960s in IBM's La Gaude laboratory near Nice in southern France.
context_page_description: In 1969 IBM started marketing in five European countries the IBM 2750 Switching System – worldwide, the first stored-program-controlled PABX. Previously only electromechanical Strowger and Crossbar PABXs were available.
  The family of IBM 1750, 2750 and 3750 Switching Systems was developed from the IBM 1800 by the IBM La Gaude Research Laboratory near Nice, France for European markets only. Each system included twin stored-program controllers, twin disks, 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 Montpellier factory.
context_section_description: Most management facilities were new to the PABX market:
  IBM 3755 Operator Desk: optionally with braille-coded keys and audible alarms
  Extension number and facility changes made from a central keyboard
  Call cost recording
  Classes of service for extensions
  Traffic analysis
  Night service: pre-night, standard, special-type-1, and special-type-2 night services.
caption: Centralised IBM 3755 Operator Desks could handle calls for multiple 3750s and 1750s dispersed across a country.
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