SMS Technology

The SMS technology was created in Europe, by GSM pioneers. The standardization process is lead by the European Telecommunications Standards Institute (ETSI). The SMS technology was created to provide an infrastructure for the transportation of short messages containing a maximum of 140 bytes (8 bit objects) of useful data in mobile telecommunication networks. The transportation is done in the GSM signaling path in traditional GSM networks, and as GPRS packets in GPRS networks. The messages are composed using the PDU specification. An SMS is a binary string, that contains all the necessary information to form the message header needed for transportation and the message body that contains the payload. The basic addressing scheme of SMS messages are mobile telephone numbers called MSISDN. 

SMS technology fact sheet:

Standard:	GSM (ETS 03.40)
Transport technology:	GSM Signaling Path , GPRS
Transport protocol:	Short Message Protocol
Addressing scheme:	MSISDN
Message description language:	SMS PDU
User data length:	140 byte (Concatenated messages can exceed this size)
Basic character set:	7-bit SMS, 8-bit SMS, UCS2