The character limit for a single SMS message is 160 characters, however most modern phones and networks support concatenation and segment and rebuild messages up to 1600 characters. Messages not using GSM-7 encoding are limited to 67 characters.
When you send a SMS message over 160 characters the message will be split. Large messages are segmented into 153 character segements and sent individually then rebuilt by the recipients device. For example, a 161 character message will be sent as two messages, one with 153 characters and the second with 8 characters.
If you include non-GSM characters like eastern characters in SMS messages, those messages have to be sent via UCS-2 encoding. Messages containing any UCS-2 characters are limited to 67 characters and will be concatenated into 67 character message segments, even if the messages contain less than 160 characters.
