SMS Encoding

IntelePeer supports two main types of encoding, which are dynamically switched based on the characters you enter in the message text:

  • GSM-7

    • A standard alphabet for SMS messages containing the most commonly used letters and symbols.

    • Seven (7) bits are used to send a single character with GSM-7 encoding. Since SMS messages are transmitted as 140 8-bit octets, a message encoded with GSM-7 can contain up to 160 characters: (140*8)/7 = 160.

    • If concatenated messages are used, a User Data Header of six (6) bytes is used so the receiving device can re-assemble the messages. This leaves 153 GSM-7 characters available per single SMS message segment.

  • UCS-2

    • An expanded alphabet for SMS messages containing additional characters and alphabets (for example, Korean, Chinese, and Arabic).

    • Sixteen (16) bits (2 bytes) are used to send a single character with UCS-2 encoding. Since SMS messages are transmitted as 140 8-bit octets, a message encoded with UCS-2 can contain up to 70 characters: (140*8)/(2*8) = 70.

    • If concatenated messages are used, a User Data Header of six (6) bytes is used so the receiving device can re-assemble the messages. This leaves 67 UCS-2 characters available per single SMS message segment.

With this simple tool, you can check the following:

  • Which encoding type will be used for your message

  • The number of characters in your message

  • How many segments your message will be split into

Here are some tips and tricks to keep your SMS short and keep cost down:

  • Make sure you use only the following GSM-7 characters instead of UCS-2 characters:

    @£$¥èéùìòÇ`Øø`ÅåΔ_ΦΓΛΩΠΨΣΘΞ`ÆæßÉ!"#¤%&'()*=,-./0123456789:;<=>?¡ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÑÜ`¿abcdefghijklmnopqrstuvwxyzäöñüà

  • Use the old-fashioned : ) or ; ) instead of emojis, which are UCS-2 characters

  • Use abbreviations and try to shorten words (for example, 2gether vs together, or 4ever vs forever)