> For the complete documentation index, see [llms.txt](https://docs.lightpost.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lightpost.app/core-concepts/groups/sms/text-encoding.md).

# SMS and Text Encoding

SMS messages use a **character set** called **GSM-7 encoding** by default, which supports **160 characters** per message. 

SMS message length can be **severely restricted** when using **special characters** that are outside this character set.

Any character outside the predefined GSM-7 character set (such as certain symbols, emojis, or special punctuation), switches the message to use UTF-16 (UCS-2) encoding, which reduces the character limit to 70 characters per message.

#### Avoid using special characters

Restricting character usage to a **regular apostrophe**, a dash instead of a long dash, or three periods instead of an ellipsis is a way to work around this limited character set.

If you’re **copying/pasting** your message from another program like **Word**, they will often times carry over these special characters, for example.

#### iPhone issues with special characters

**iPhones** use a **special character** by default for the **apostrophe** (for example in auto-correct). When typing and it auto-replaces it, you can delete it, then press the "123" button to see special characters: tap and hold on the apostrophe and you will see other options, including one that looks more like a straight line for an apostrophe. This is the "regular" apostrophe.