Week 8 - Common Data Structures - SMS

Question 1

What is SMS and how many characters does it support?

Answer 1

SMS = Short Message Service

Up to 160 characters.

Larger messages sent / recieved in multiple parts. SMS concatenation occurs where markers are used to indicate the order of the messages to be read

Question 2

What are the two methods that SMS can be transmitted / recieved?

Answer 2

• Text mode. Text is transmitted in plain text. Not supported by all devices
• Protocol Discription (PDU) mode. This is most common. Decoding is automatically handled by the device.

Question 3

What protocol defines the three sets of alphabets / character sets used in PDU mode?

Answer 3

GSM 03.38 protocol

Question 4

What are the 3 sets of alphabets / character sets defined by GSM 03.38?

Answer 4

• GSM 7 bit (160 characters). This is most common
• 8 bit data (140 characters)
• 16 bit Universal Character Set (70 characters)

Question 5

What is a Septet?

Answer 5

A data type used by PDU mode.
A septet is a group of 7 bits in INTEGER encoding ( 0 to 127)

Question 6

What is an Octet?

Answer 6

A data type used by PDU mode.
An octet is a group of 8 bits in HEX format (0x00 to 0xFF)

Question 7

What is a semi octet?

Answer 7

A data type used by PDU mode.
Group of 8 bits in INTEGER coding (0 to 153)