# 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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.lightpost.app/core-concepts/groups/sms/text-encoding.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.