def strhex2bin(strhex):
    """
    Convert a string representing an hex value into a 
    string representing the same value in binary format.
    """
    dic = { '0':"0000",
            '1':"0001",
            '2':"0010",
            '3':"0011",
            '4':"0100",
            '5':"0101",
            '6':"0110",
            '7':"0111",
            '8':"1000",
            '9':"1001",
            'A':"1010",
            'B':"1011",
            'C':"1100",
            'D':"1101",
            'E':"1110",
            'F':"1111"
    }
    binstr = ""
    for i in strhex:
        binstr = binstr + dic[i.upper()]
    return binstr