11.07.2015 Views

UNIVERSITI TEKNOLOGI MALAYSIA - FKE - UTM

UNIVERSITI TEKNOLOGI MALAYSIA - FKE - UTM

UNIVERSITI TEKNOLOGI MALAYSIA - FKE - UTM

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

354.3.3 Null Character ProblemFigure 4.6 Overview of Communication between GPS receiver (MS1E) & ClientCommand Center DriverThe present of NULL character (ASCII 0 or Hex 00) within the PDUmessage causes the message being truncated by the Comm. Driver at ClientCommand Center (Stage 3).At stage 1, the modem driver at MS1E (AT_SM_Modem) adopts SMSPDU mode to send GPS data packets via wireless modem.The user data in PDU mode is sent to SMS Center in binary format for example:0A10412274E600000000043AFF210013000500 (hex)As we can notice here, there are 7 Null Characters in the PDU message.At stage 2, the user data (binary format) is received by SMS Center andtransferred to client command center communication driver via direct TCP/IPLink.Here, the user data is still in binary format as the following:

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!