The telegram FAQ says that it cannot be used for voice calls: https://telegram.org/faq#q-can-i-make-calls-or-video-calls-via-telegram https://telegram.org/faq#

The telegram FAQ says that it cannot be used for voice calls: https://telegram.org/faq#q-can-i-make-calls-or-video-calls-via-telegram https://telegram.org/faq#q-can-i-make-calls-or-video-calls-v...