C_OCTET( instancia, service_type, 6 );
C_OCTET( instancia, message_id, 65 );
    U08( instancia, source_addr_ton, str_addr_ton );
    U08( instancia, source_addr_npi, str_addr_npi );
C_OCTET( instancia, source_addr, 21 );
    U08( instancia, dest_addr_ton, str_addr_ton );
    U08( instancia, dest_addr_npi, str_addr_npi );
C_OCTET( instancia, destination_addr, 21 );
