A simple illustration of a half-duplex walkie talkie communication system.
<a href="https://en.wikipedia.org/wiki/User:Greggreggreg" class="extiw" title="wikipedia:User:Greggreggreg">Greggreggreg</a> at <a href="https://en.wikipedia.org/wiki/" class="extiw" title="wikipedia:">English Wikipedia</a>
2 February 2007 (original upload date)
Transferred from <span class="plainlinks"><a class="external text" href="https://en.wikipedia.org">en.wikipedia</a></span> to Commons.