Can divorce take place through telephone? Does divorce occur if a man tells his wife on the telephone, "I have a witness with me and I am divorcing you with three talaqs"?

Dear Brother / Sister,

Mujtahid scholars set examples and shed light to all scholars with the fatwas they gave up to now. Therefore, we take their fatwas directly in almost all issues or if the fatwa is similar, we benefit from their fatwa and enlighten the issue. The same thing is in question here. 

There was no telephone during the time of mujtahid scholars but they gave a decree on divorcing by sending a letter. The scholars of today benefited from it since it is similar to telephone. That is, they said, “A man can divorce his wife through telephone, letter and email by using a clear expression.”

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