Pc-connector gh.jpg
PC-socket, greatly magnified
General specifications
Hot pluggable Yes
Audio signal None
Video signal None
Pins 2

A Prontor-Compur connection (also known as a PC connector, PC terminal, or PC socket) is a standard 3.5 mm (1/8") electrical connector (as defined in ISO 519[1]) used in photography to synchronize the shutter to the flash.[2]


A leaf shutter
A leaf shutter

"Prontor" has its origins in the Italian word "pronto", meaning ready (and was a leaf shutter made by Alfred Gauthier [de]).[3] "Compur" is derived from the word "compound" (the "Compound [de]" was a long-lived series of leaf shutters made by Friedrich Deckel [de]).


The term is derived from brands of widely marketed photographic leaf shutters manufactured from the early 1950s by two distinct, but now defunct German companies. Gauthier [de] (which made the Prontor-S and Prontor SV models, amongst others) and Deckel [de] (the Synchro-Compur model, successor to the Compound model).

Both companies' brands, Prontor (from 1953) and Compur (from 1951), shared a common 1/8"-inch coaxial connector for shutter–flash synchronization. This convergence of design is not as coincidental as it might first appear, owing to the fact that the Zeiss organisation held a significant shareholding in both of these companies prior to the introduction of the shared connector.[4] By the 1950s, Gauthier were manufacturing up to 10,000 Prontor shutters daily.

The Gauthier company's essence lives on as Prontor GmbH [de], which is a wholly owned subsidiary of VTC Industrieholding GmbH [de].[5] The Deckel company went bankrupt in 1994.[citation needed]


  1. ^ ISO 519:1974, ISO 519:1992 (1992-11-25). Photography -- Hand-held cameras -- Flash-connector dimensions. Geneva: International Organization for Standardization.
  2. ^ Axford, Norman; et al. (2000). Manual of Photography: Photographic and Digital Imaging. Focal Press. ISBN 0-240-51574-9.
  3. ^ History of the Prontor company. http://www.prontor.de/go/unternehmen-firmengeschichte/english.html
  4. ^ History of flash photography. http://www.photomemorabilia.co.uk/Ilford/Flash_History.html
  5. ^ "Timeline of Prontor company".