Shows affected included ITV's The X Factor, Channel 4's Richard and Judy and BBC1's Saturday Kitchen.
The new measures aim to give viewers a better understanding of their chances of getting through to a programme as well as clearer information about the cost of the call.
Coming in place in one month's time, Icstis believes the rules will address the concerns raised by MPs on the Culture, Media and Sport select committee in January this year.
Icstis chief executive George Kidd said: "We believe these new measures, which are designed to address the concerns that have been raised recently, will go a long way to restoring consumer trust in this form of TV quiz.
"We have acted at great speed and have worked closely with [media regulator] Ofcom, broadcasters, programme makers and telephone companies, who have all been supportive in making sure that the changes could be introduced as soon as possible."
Among the news rules for broadcasters, presenters or voice-overs must announce at intervals of no more than ten minutes how much prices cost to take part in a show and call cost warnings must be provided to callers for each £10 spent in a day.
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