Not sure if this is what you were after, but the ascii values for the mirc control codes are... ctrl+k - 3 , ctrl+b - 2 , ctrl+u - 31 , ctrl+r - 22 , ctrl+o - 15
Without looking into it which i am unable to do atm, i can't say for sure if mirc just sends the plain control codes (little boxes are they appear i guess), but ctcp's send and recieve this way so it would be a fair assumption.