Many people know the difference between "translation" and "interpreting". The former is transforming text written in one language into text written in another one, preserving the original meaning. The latter is translating one spoken language into another spoken language, again to convey the same meaning. 

However, many people get confused about available modes of interpreting. The question is: how to select the right type of interpretation? Below, you can read a short explanation that highlights important differences between interpreting modes, connects them to specific types of meeting and venue also providing a high-level description of equipment you may need depending on the kind of meeting you have in mind.
Simultaneous interpretation (i.e. „happening at the same time”) – general  description:
  • the interpreter translates continuously, during the speaker’s utterance; thus, the meeting’s duration is not extended;
  • it is performed by a team of interpreters (2-3 persons);
Versions of simultaneous interpretation:
  • simultaneous interpretation from a booth:
  • performed from an adequately equipped booth (details below)
  • useful for any number of listeners when the venue can accomodate
    a mobile booth or has a built-in one
  • simultaneous interpretation via infoports:
  • performed with the use of a small portable set of microphones
    and headsets instead of a booth;
  • useful when the room is small (no space for a booth) and quiet,
    and the number of persons present does not exceed 15-20 (speakers and interpreters included);
  • whispered simultaneous interpretation ("chuchotage”):
  • interpreters and their listeners listen to speech without using electroacoustic aids;         
  • feasible if the number of persons who listen to the interpreters' delivery does not exceed 2;         
  • some meetings leave no alternative but in my opinion, this mode should be applied only exceptionally as it appears “makeshift” and causes discomfort to listeners and all others present;
  • in most cases, infoports should be considered a superior alternative to chuchotage
Consecutive interpretation (i.e. “closely following”) - general description:
  • the interpreter translates in an interrupted fashion, taking turns with the speaker;  
  • it is performed by 1-2 interpreters with minimal equipment requirements (a standard sound system
    suffices in most cases);         
  • it extends the duration of the meeting (or shortens the time available to the speaker);         
  • useful at training courses when the audience require more time to take notes and immediately clarify doubts.
Sight translation (in latin languages somewhat romantically termed "translation at first sight") - general description:
  • called "translation" because the source material is written but is also akin to interpreting because the delivery is spoken;
  • indispensable at multilingual audits and inspections where sight translation of source documents is key;
  • often regards handwritten notes, hence, may require "insider" knowledge of notation patterns in a given discipline.
Matching simultaneous interpreting with equipment:
  • simultaneous interpreting from a booth  – requires at least:
  • a booth (with appropriate hardware) for every team of interpreters and (frequently) for every language pair (details of interpreting at a multilingual conference exceed the scope of this short guide);
  • microphones for speakers (interpreters in the booth
    only hear what reaches their headsets via the microphone);
  • headsets for the audience (listeners cannot hear the
    interpreters without them);
  • equipment, which amplifies, transfers and routes acoustic signals;
  • simultaneous interpreting via infoports – requires:
  • a portable set of microphones and headsets delivered in a suitcase, which also contains a radio-frequency transceiver that connects the microphones and headsets.