G.114
Encyclopedia
G.114 is an ITU
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...

recommendation that addresses acceptable delays for voice applications, is oriented to national telecommunications and is more stringent than what is normally applied in private voice networks.

One of the things it addresses is voice delay. It says < 150 milliseconds is acceptable, > 400 milliseconds is unacceptable and in between people should be made aware of quality issues.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK