What is Linked SMS?
A standard SMS can contain up to 160 characters. If you need to send longer messages, APSIS Pro offers the Linked SMS feature. This allows you to write a long message that is automatically split into multiple SMS during sending and then recombined on the recipient’s phone, appearing as one continuous message.
How It Works
Each part of a linked SMS is treated as a separate SMS and charged individually.
Due to technical requirements, each concatenated SMS in a linked message is limited to 153 characters instead of 160.
This is because of User Data Headers (UDH), which enable mobile phones to link multiple messages together.
Special Characters
If your message contains one or more special characters (not included in the GSM character set 03.38, such as Arabic, Chinese, Japanese, or Cyrillic), the character limit changes:
Regular SMS with special characters: 70 characters.
Linked SMS with special characters: Each segment is limited to 67 characters due to additional encoding requirements.
✅ Summary:
Standard SMS: 160 characters.
Linked SMS: 153 characters per segment.
With special characters: 70 characters (regular) or 67 characters (linked).
Each segment is billed separately.
