Telegram use natively UTF-8 and you need a UTF-8 to ASCII to RouterOS converter.
The function FuncCP1251toUTF8 (really made with feet) and also my version for CP1252 (not the best, but more clear)
http://forum.mikrotik.com/t/rextended-fragments-of-snippets/151033/1
Is clearly called to_UTF8 because convert RouterOS ASCII characters received to CP125x and to UTF-8 for use it on Telegram & Co.
Instead from Telegram if non-7-bit ascii text (Cyrillic, emoticon & Co.) is used, you receive UTF-8 and RouterOS is unable to directly understand.