UNIVERSITI TEKNOLOGI MALAYSIA - FKE - UTM

304.3.2 The PDU formatBefore we begin writing the source code, we need to know the format ofthe data we are sending or receiving. For this project, I am using SMS to send thedata back to the server. There are two ways of sending and receiving SMSmessages: by text mode and by PDU (protocol description unit) mode. The textmode (unavailable on some phones) is just an encoding of the bit streamrepresented by the PDU mode. If text mode is used, the application is bound to (orlimited by) the set of preset encoding options. In some cases, that's just not goodenough. If PDU mode is used, any encoding can be implemented.4.3.2.1 Sending / Receiving a message in PDU modeExample a message ‘hellohello’ in PDU mode:07 917283010010F5 040BC87238880900F10000993092516195800AE8329BFD4697D9EC37This octet sequence consists of three parts: An initial octet indicating the length ofthe SMSC information ("07"), the SMSC information itself ("917283010010F5"),and the SMS_DELIVER part (specified by ETSI in GSM 03.40).Octet(s)Description07 Length of the SMSC information (in this case 7 octets)9172 83 01 00 10 F5Type-of-address of the SMSC. (91 means internationalformat of the phone number)Service center number(in decimal semi-octets). Thelength of the phone number is odd (11), so a trailing Fhas been added to form proper octets. The phone numberof this service center is "+27381000015". See below.04 First octet of this SMS-DELIVER message.0BAddress-Length. Length of the sender number (0B hex =11 dec)