def _inc_encode(ie):
        encoded=list()
        hop=17 # make it something odd
        final=False
        for i in range(0,len(gsm_alpha),hop):
            end=i+hop
            if end>=len(gsm_alpha): final=True
            encoded.append(ie.encode(gsm_alpha[i:end],final))
        return ''.join(encoded)