Cannot send two digit number using realterm to xilinx microblaze through serial port
A byte can be between 0 and 255. If you send, for example, decimal 65 then the system will translate it to 'A'. Once you've received the byte, 'A', just convert it to an integer with (unsigned int)ReceiveBuffer[i]. You'll get 65.

Another approach would be breaking the 2-digit-number into the digits and sending each digit respectively.