Our customers frequently ask which characters can be sent in a text message. This article will help you understand the SMS character set and the best practices for composing a text message.
SMS character set
Most of the mobile networks use the GSM standard, so a standard text message on these networks is restricted to the GSM character set. A single SMS message may contain a maximum of 160 characters. However, each of the characters must be part of the so-called 7-bit default alphabet as specified by GSM 3.38 character set. This character set contains all ASCII characters and some accented characters.
An SMS can contain up to 140 bytes. A byte is 8 bits. Since the GSM character set is encoded using 7-bits, this means there can be 160 characters in an SMS. The 7-bit encoding limitation means only 128 standard characters would be possible. The GSM standard gets round this by also having the Extended GSM character set. These are another 10 characters which are actually sent by sending two 7-bit characters, an escape (ESC) character followed by another character. This means, for example, that 160 "$" characters can fit in a single SMS, but not 160 "{" characters –since "{" is not present in standard character set.
NOTE: Using any character that is not in the GSM character set will cause the SMS message to be treated as a Unicode SMS message–which has a length limit of 70 characters due to the different character encoding. |
Long SMS Messages
An SMS message that has more than 160 characters–or more than 70 characters in a Unicode message–is considered to be a long message. Long messages are split into multiple messages and will be received sequentially at the recipient mobile phone. For long messages, the maximum number of characters in each message is 154 (64 characters for Unicode messages). The remaining characters are used for sequencing the messages.
Common Mistakes while Composing an SMS Message
Many people use Microsoft word or similar text editors to compose an SMS message. The message appears fine until it reaches the mobile network carrier. If the message contains characters other than the ones specified in GSM character set, a normal English message can be treated as a Unicode message, or in some cases the message text can be garbled.
Some common characters that you should avoid using to ensure your message is sent using the more efficient GSM character set are as follows:
Keep in mind that, although you may press the same keystroke, the character encoding actually depends on the text editor that you are using.
Tip for business texters: For composing text messages in standard English language, use plain text editors such as Notepad instead of rich text editors such as Microsoft Word. This will minimize the risk of your message being converted into a Unicode message. |