Hello, When I send a SMS to a particular port, where is this port number stored in the header. From where does the destination mobile read the destination port. I saw the structure of the PDU and found no field for destination port. In case of Ringing tones, operator logo, CLI and other smart messages the PDU has field for destination port number. I read some posts mentioning usage of "TP-User-Data" field for this purpose. Can this field be used for destination port? Can these messages invoke my MIDlet listening on that port?