SMS Format and Encoding

An SMS message is short by nature. Each SMS message is limited in size to 1120 bits. Each character included in a message requires a set number of bits to encode its data for transmission. The number of bits required for each character is determined by the type of encoding used for transmission.

  1. Possibilities and Limitations with SMS

SMS messages are text-only. The following special format limitations apply.

Supported

  • SMS messages with the character encoding UTF-8 can contain special characters.
  • SMS messages can contain links to your website. Use %link% to shorten your campaign link.
  • SMS messages can contain personalizations (both placeholders and complex personalizations).
  • SMS sendouts can be limited by a selection. Apply a selection to an SMS message during sendout for more targeted messaging.

    • Not Supported

  • SMS messages do not contain a subject line.
  • SMS messages do not support images.
  • SMS messages do not support attachments.
  • SMS messages have a maximum length that depends on the type of character encoding.
  • SMS messages sent with 7-bit encoding (ISO 8859-1 or ISO 8859-15) or are limited to 160 characters per message.
  • SMS messages sent with 16-bit encoding (UTF-8) are limited to 70 characters per message. 16-bit encoding allows special characters.

    1. Message Encoding

    SMS messages use either 7-bit or 16-bit encoding.
    SMS messages sent with 7-bit encoding (ISO 8859-1 or ISO 8859-15) or are limited to 160 characters per message.
    SMS messages sent with 16-bit encoding (UTF-8) are limited to 70 characters per message. 16-bit encoding allows special characters.
    SMS messages use 7-bit encoding by default. For a complete list of characters supported by this alphabet, see GSM_03.38
    Allowed chars for 7-bit encoding (160 chars in 1 sms)

    Basic Character Set[2]
      0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70
    0x00 @ Δ SP 0 ¡ P ¿ p
    0x01 £ _ ! 1 A Q a q
    0x02 $ Φ " 2 B R b r
    0x03 ¥ Γ # 3 C S c s
    0x04 è Λ ¤ 4 D T d t
    0x05 é Ω % 5 E U e u
    0x06 ù Π & 6 F V f v
    0x07 ì Ψ ' 7 G W g w
    0x08 ò Σ ( 8 H X h x
    0x09 Ç Θ ) 9 I Y i y
    0x0A LF Ξ * : J Z j z
    0x0B Ø ESC + ; K Ä k ä
    0x0C ø Æ , < L Ö l ö
    0x0D CR æ - = M Ñ m ñ
    0x0E Å ß . > N Ü n ü
    0x0F å É / ? O § o à
    • LF is a Line Feed control.
    • CR is a Carriage Return control, or filler.
    • ESC is an Escape to extension table (maps to NBSP).
    • SP is a Space character.
    Basic Character Set Extension[2]
      0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70
    0x00         |      
    0x01                
    0x02                
    0x03                
    0x04   ^            
    0x05             €  
    0x06                
    0x07                
    0x08     {          
    0x09     }          
    0x0A FF              
    0x0B   SS2            
    0x0C       [        
    0x0D CR2     ~        
    0x0E       ]        
    0x0F     \          
    • FF is a Page Break control. If not recognized, it shall be treated like LF.
    • CR2 is a control character. No language specific character shall be encoded at this position.
    • SS2 is a second Single Shift Escape control reserved for future extensions.

    If you use characters that the GSM 7-bit alphabet does not support, then the encoding switches automatically to 16-bit. Mapp Engage automatically reduces the maximum message length to 70 characters.