Signal & Syntax · Messaging and A2P

What Is GSM-7 Encoding?

GSM-7 is the default 7-bit SMS alphabet. A single GSM-7 message holds 160 characters, and a split message holds 153 per segment.

Also calledGSM 03.38 · GSM default alphabet

Example

160 single · 153 per segment

GSM-7 in Practice

GSM-7 covers Latin letters, digits, common punctuation and a set of accented characters. The extension characters, including € and {, take two units each. One character outside the set switches the whole message to UCS-2. A curly apostrophe is the usual culprit.

Where ScoreMachine Fits

ScoreMachine

The SMS Segment Counter flags every character that forces UCS-2.

Related Terms

UCS-2 UCS-2 is the 16-bit SMS encoding for characters outside GSM-7. SMS segment An SMS segment is one part of a message split across two or more SMS. SMS SMS (Short Message Service) is the text messaging service built into mobile networks. Delivery receipt A delivery receipt (DLR) is the status report an operator returns for each SMS.

Read the Guide

Guide

GSM-7, UCS-2 and SMS Segments Explained

How one character changes the segment count. Read the guide →

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