SMS Message Formatting & Charging

Standard Messages

A standard SMS text message can contain up to 160 characters of information and is charged as one SMS message. A standard message is defined as using characters from the default UK alphabet that are in 7-bit format (see table 3, below). It is possible to select, from a qwerty keyboard, information characters outside of this standard character set. These additional characters can be either Extended Characters or International Characters.

 

Extended Characters

There are 9 Extended Characters available from the standard UK keyboard (see table 4, below). Each Extended Character requires 8 bits and therefore takes up two 7-bit characters. If an SMS message is formed from standard 7-bit characters but one Extended character is used then the maximum character size of the SMS message is reduced by 1 to 159 characters, and so on, for each additional Extended character. These ‘reduced in size’ messages are still charged at the same 160 character message price as the total bits transmitted remain the same.

When sending SMS from a Connect or Flare web-account the Compose page will show a warning message if an Extended Character is used. In this case, the page will display the total characters in the message, which includes any additional characters used to support the Extended Characters.

 

International Characters

An International Character requires 16 bits to be transmitted. If a single International Character is used the entire message has to be encoded in a 16-bit format which reduces the size of the SMS message to 70 characters (140 Octets of 8 bits). These ‘reduced in size’ messages are still charged at the same 160 character message price as the total bits transmitted remain the same.

If you are sending from a Connect or Flare web account the Compose page will show a warning message if an International Character is used and the character and message count is amended accordingly.

Long or Concatenated messages

It is possible to send Long messages of more than 160 characters to mobile phones that use the Enhanced Message Service. Messages of greater than 160 characters are divided up or concatenated into separate SMS message parts that contain extra information so that the receiving mobile phone hand set can re-combine them into a single received message.

Critico limit the size of the Long message to 10 concatenated SMS message parts. Each concatenated message part is charged as one SMS message. So a Long message could cost up to 10 SMS messages.

To enable the Long message parts to be re-combined in the hand set a header is included within each SMS message which takes seven 7-bit characters. Hence a Long message over 160 characters (7-bit) will cause the first message to be reduced in length by 7 characters and these will be sent in the second message. So for example, if a single Long message of 161 characters (7-bit) is sent then this is actually transmitted and billed as two SMS messages; The first containing the first 153 characters, and the second, the remaining 8 characters. This is extended to the third, fourth, up to tenth message parts, as follows:

 

Table 1:Long Message Characters

 

Number of SMS	Maximum usable characters (7-bit)
1	160
2	306
3	459
4	612
5	765
6	918
7	1071
8	1224
9	1337
10	1530

If you are sending from a Connect or Flare web-account the Compose screen will indicate how many chargeable SMS message parts will be used to send the Long message based on the above table. This will not be the case if using other electronic entry methods, including SOAP/XML and Excel Plugins, or using the email to SMS service.

A similar scenario exists for International characters (16-bit) but in this case, the header reduces the characters by 3 rather than 7. So an International Long message of 71 characters will cost two SMS messages, where the first will contain the first 67 characters and the second the remaining 4 characters. And this is same for each of the third, fourth, up to tenth SMS message parts, as follows:

Table 2: International Long Message Characters

 

Number of SMS	Maximum usable characters (16-bit)
1	70
2	134
3	201
4	268
5	335
6	402
7	469
8	536
9	603
10	670

If you are sending from a Connect or Flare web-account the Compose screen will indicate how many chargeable SMS message parts will be used to send the International Long message based on the above table. This will not be the case if using other electronic entry methods, including SOAP/XML and Excel Plugins, or using the email to SMS service.

Note that the re-combining of the Long message parts is a function of both the mobile phone hand set and destination mobile phone networks, which are subject to change and revision from time to time and therefore beyond Critico control.