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Isochronity (from ancient Greek ἰσόχρονος isóchronos , German 'equal to time , equal age' ) is

  • the property of a technical system, in particular a network or other transmission system, to perform defined tasks within a precisely defined period of time. Isochronous telecommunication networks can transmit error-free at a constant data rate .

Isochronous transmission

With this type of transmission, there is always a fixed number of steps between any two identification points. The time interval between two transmitted bits is always the same. Temporal deviations, which are referred to as jitter , ideally do not exist. In practice they have to be limited.

Since constant clock signals are used in practice, all types of transmission are isochronous at least within a "hierarchy block". Example: The serial RS232 interface referred to as asynchronous sends bytes asynchronously, i.e. at any time - the start, data and stop bits are sent isochronously.

The term isochronous transmission is still used in technology with a slightly different meaning: Here one understands that a certain, minimum data rate is guaranteed (e.g. Firewire , USB ...). This is important for multimedia ( video on demand, etc.) or real-time applications (air traffic control, etc.) , for example .


  • In clocks , the uniformity of vibrations is called isochronism , i.e. their frequency constancy , which is independent of external interference.


  • Martin Padeffke: Design process for asynchronous circuits using standard software. 1st edition, Cuvillier Verlag, Göttingen 2005, ISBN 3-86537-471-9 .
  • Anatol Badach, Erwin Hoffmann: Technology of the IP networks. Internet communication in theory and use, 3rd edition, Carl Hanser Verlag, Munich 2015, ISBN 978-3-446-43976-4 .
  • Bernhard Tritsch: Distributed learning in computer networks. A tele-media training architecture, Springer Verlag, Berlin / Heidelberg 1997, ISBN 978-3-540-62085-3 .
  • Franz-Joachim Kauffels: Local Networks. 1st edition. Redline, Heidelberg 2008, ISBN 978-3-8266-5961-4 .

Individual evidence

  1. ^ Wilhelm Pape , Max Sengebusch (arrangement): Concise dictionary of the Greek language . 3rd edition, 6th impression. Vieweg & Sohn, Braunschweig 1914 ( [accessed on February 4, 2019]).

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