SMS Format and Encoding

General Information

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.

Possibilities and Limitations

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

Supported

• Special characters: SMS messages with the character encoding UTF-8 can contain special characters.

• Links: SMS messages can contain links to your website. You can shorten the URL by clicking ​Shorten Links​ in step ​2. Content​ of the message creation wizard. Note that Mapp Engage cannot track whether your recipients click these links.

• Personalizations: SMS messages can contain personalizations (both placeholders and complex personalization).

• Mapp Engage Variables: SMS messages can contain Mapp Engage Variables and coupons.

• Segmentation: A segment can limit SMS sendouts. To send more targeted messages, apply a segment to an SMS message during sendout.

Not Supported

• Subject lines

• Images

• Attachments

• The maximum length depends on the character encoding type:

  • 7-bit encoding (ISO 8859-1 or ISO 8859-15) - limited to 160 characters per message.

  • 16-bit encoding (UTF-8) - limited to 70 characters per message. 16-bit encoding allows special characters.

Encoding​

SMS messages use either 7-bit or 16-bit encoding and are sent using the 7-bit encoding by default. For a complete list of characters supported by this alphabet, see http://en.wikipedia.org/wiki/GSM_03.38.

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

Concatenation​

Concatenated SMS overcomes the character limitation for single SMS messages. Using this method, Mapp Engage splits messages exceeding the single message limitation into as many as three smaller messages. The receiving device reassembles the message parts. Instead of three separate messages, the recipient sees a single text message.

Not every mobile carrier supports concatenated messages.

Each message sent by Mapp Engage includes a header that contains instructions for message reassembly. Because the headers used to reassemble the message increase the size of each message part, the actual maximum size of the SMS is lower.

The message limitation for concatenated SMS messages is shown in the following table:

If your SMS Message contains a link, you can gain more space by pressing the ​Shorten Links​ button. For more information, see Add Links to SMS.

Character Count

Below the message input field, the system indicates the current number of characters used in the SMS. You also see how many SMS messages are needed to send the entire message. The system also recognizes the character format currently in use.

Placeholders and text created through personalization and Mapp Engage Variables cannot be checked for length by the system. The placeholders are replaced with content during sendout. If the SMS character limit is exceeded because of personalization, additional SMS messages are sent.