Getting the most bang out of each buck in a marketing communication strategy requires solids budget estimation. Yet when the budget is broken halfway through the month, the questions arise: How did this happen? How have we sent twice as many SMS messages than we should have at this point? Well, this is where the multipart SMS comes into play.
The GSM 03.38 character set (definitely a technical term, bear with me) is the most commonly used encoding method when sending messages. It is a 7-bit alphabet, limiting 7-bit encoding to 160 characters. This means only specific characters can be used to achieve the maximum length of content.
Compared to the GSM character set, Unicode (UCS-2) encoding supports a much greater range of characters and languages, thus providing more options for content. So, if a message contains any characters not listed in the 7-bit alphabet, UCS-2 encoding is the default, and message length is reduced to 70 characters. To put it into perspective: If any of the characters used in a message that is not present in the 7-bit alphabet, the maximum length of one SMS messages becomes 70 characters, not 160.
Further, if a message exceeds 160 characters under GSM encoding, or 70 characters under UCS-2 encoding, an SMS is forced to be split, sending texts to the handset separately, with each SMS charged separately. Also note that the character limit per text in a multipart SMS is smaller –153 for 7-bit encoding and 67 for UCS-2.
So how can this break the budget. Let’s say a campaign is created to send messages to 3,000 people, and the SMS template calls for 155 characters, well within the limit of a single 7-bit message. But one of the characters in the message happens to fall out of the 7-bit alphabet, so the entire message is encoded using UCS-2. Suddenly what was expected to be 3,000 messages becomes 9,000 messages. Most importantly, 9,000 messages are charged to the account. This can happen in instances when a language specific letter is used, such as “ñ,” or even when using a different type of space.
To help avoid budget breakers, Messente developed the following two tools:
- The SMS Length Calculator - Check the message content for characters used, the estimated message length, and ways to optimize campaigns.
- The Auto Replace – Messente’s software automatically replaces Unicode characters with similar GSM-friendly characters.