Single Text Message: The length of a single text message is 160 characters, including spaces.
Multi-part SMS: If you send an SMS whose length is over 160 characters, Exotel will treat it as a multi-part SMS. This multi-part SMS will be sent to your customer as a single SMS.
The maximum length of a single SMS in a multi-part SMS is 153 characters. This is due to the need for user-data headers (UDHs) information. Mobile phones use UDH information to enable them to link long messages together so that they appear as single SMS messages in recipient's phone inbox.
You could send up to 1000 characters as multipart message which will be split into 7 messages internally.
This refers only to messages that contain the standard GSM 03.38 character set.
Characters allowed in an SMS
The standard SMS mobile-phone character set is used universally to send text messages. The standard character (GSM 03.38 Encoding) set allows up to 160 characters, and includes few of the Roman alphabet and the most common accented forms, certain special characters, and few Greek alphabets. It includes the following characters:
@ £ \ $ ¥ è é ù ì ò Ç \ n Ø ø \ r Å å ? _ F " ? O ? ? S T ? Æ æ ß É ! \ " # ¤ % & ' ( ) * + , - ../ 0 1 2 3 4 5 6 7 8 9 : ; < = > ? ¡ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ? Ö Ñ Ü § ¿ a b c d e f g h I j k l m n o p q r s t u v w x y z ö ñ ü à ä Ä { } \ ~ [ ] |
Number of SMS |
Number of characters in linked message |
1 |
160 characters |
2 |
306 characters (2 * 153) |
3 |
459 characters (3 *153) |
… |
|
7 |
1000 characters (6 *153 + 1 * 82) |
SMS in languages other than English
When using non-GSM 03.38 characters (mentioned in the paragraph above), the SMS is transmitted as a Unicode message. The Unicode character support provides the ability to send a message in Hindi, Kannada, Tamil, etc.
If the message contains even a single Unicode character, the entire message will have to be converted into Unicode.
The maximum length of a Unicode SMS is 70 characters per SMS.
If your message runs longer than 70 characters, the system will treat it as a multi-part SMS. Your customer will see it delivered as a single message but Exotel will treat it as multiple SMS-es.
The maximum length of a single multi-part SMS is 67 characters. You could send up to 500 characters as multipart message which will be split into 8 messages in the system..
Number of SMS |
Number of characters in linked message |
1 |
70 characters |
2 |
134 characters (2 *67) |
3 |
201 characters (3 *67) |
… |
|
7 |
500 characters (6 *67 + 1 * 31) |