Concatenated or Long SMS (Plain Text)
A standard plain text (7-bit)
SMS can contain up to 160 characters.
Note: There are 9 special characters that are counted as 2 individual characters.
See article on
GSM Encoding for more information.
It is possible to send multiple
SMS joined together to form a single long message.
This type of message is referred to as one of the following:
- A Long SMS
- A Concatenated SMS
- A Multipart SMS
- An Extended SMS
For the rest of this article, we will refer to such a message as a Concatenated
SMS.
A Concatenated
SMS is formed from several standard
SMS containing a 7 byte concatenation header at the beginning of each one. Since this 7 byte header is within the message, it reduces the total size of each
SMS to 153 characters each.
Note: In theorey it is possible to utilise 255 messages (39,015 characters) for a Concatenated
SMS. However, 3
SMS (or 459 characters), is generally considered to be the longest length message that will be displayed on the majority of mobile handsets.
CardBoardFish limit Concatenated
SMS to 459 characters to ensure maximum compatibility.
Note: Concatenated
SMS are billed by the number of individual
SMS messages used. If you send a 459 character message, you will be charged for 3
SMS.
CardBoardFish will automatically split long messages into the correct concatenated form for most methods of submission.
You only need to split long messages yourself if you are using one of the following protocols to submit
SMS to
CardBoardFish:
If you are using one of the above protocols, a brief description of the Concatenation User Data Header can be found below.
Concatenation User Data Header
There are 5 octets required in the User Data Header to describe a Concatenated
SMS. These are:
| Octet Number | Value | Description |
| 1 | 00 | Information Element Identifier (IEL). Does not change. |
| 2 | 03 | Information Data Length (IEDL). Does not change. |
| 3 | AA | A unique hexadecimal reference number. Does change for every set of Concatenated SMS. |
| 4 | 03 | Total number of concatenated SMS. Remains the same for each part of a Concatenated SMS. |
| 5 | 01 | Current Concatenated SMS part number. Does change for every SMS part. |
Example UDH's of a 3 part Concatenated SMS:
0003010301
0003010302
0003010303
Note: Concatenated
SMS is not supported by non
GSM networks or the United States.