As not all carriers can support some aspects of messaging functionality, Boomerang evaluates specific characteristics when selecting a message carrier for delivery:
- The length of the message
- The character set used in the content of a message
- The ability to concatenate (or join) multi-part messages together
- Specific features associated to the message
Network technologies
The Boomerang service is technology agnostic and is capable of sending and receiving SMS messages across multiple mobile network technologies. When sending a message a single standard SMS message conforms to the following:
Technology | Number of characters |
GSM: 7-Bit encoded character set | 160* |
CDMA: 8-Bit encoded character set | 140* |
Unicode:16-Bit encoded character set | 70* |
*Carrier dependent
If a Boomerang message is sent with more characters than specified above, the underlying carrier network will concatenate the messages together and deliver the full message to the end user – providing the underlying carrier network supports concatenation (Unicode concatenation is not supported by all carrier networks).
Concatenation over GSM
Where GSM is used, each concatenated text message is limited to 153 characters rather than 160 due to the inclusion of user-data header (UDH) information. Mobile phones use UDH information to enable them to link long messages together so that they appear as single SMS messages in an end user’s device inbox.
Examples of this are provided below:
Number of SMS* | Number of characters in the linked message |
1 | 160 characters |
2 | 306 characters (2x153) |
3 | 459 characters (3x153) |
4 | 612 characters (4x153) |
| 5 | 765 characters (5x153) |
Etc | 153 x Number of individual concatenated SMS messages |
Concatenation over Unicode
Unicode is a technology used when delivering non-standard (non-GSM encoded) characters within an SMS message. This could include for example Chinese, Russian or Arabic characters. Concatenated Unicode messages adhere to the following structure:
Number of SMS* | Number of characters in the linked message |
1 | 70 characters |
2 | 134 characters (2x67) |
3 | 201 characters (3x67) |
4 | 268 characters (4x67) |
5 | 335 characters (5x67) |
| Etc | 67 x Number of individual concatenated SMS messages |
*Maximum characters contained in a concatenated Unicode message is dependent on the carrier networks and the end user’s device.
Concatenation over CDMA
Where CDMA is used each concatenated text message is limited to 134 characters rather than 140 due to the inclusion of user-data (UDH) information. Mobile phones use UDH information to enable them to link long messages together so that they appear as single SMS messages in an end user’s device inbox. Examples of this are provided below:
Number of SMS* | Number of characters in the linked message |
1 | 134 characters |
2 | 268 characters (2x134) |
3 | 402 characters (3x134) |
4 | 536 characters (4x134) |
| 5 | 670 characters (5x134) |
Etc | 134 x Number of individual concatenated SMS messages |
*Message concatenation is dependent on both the network operators and the end user’s device.