SMS or text message is a very popular feature that is available on almost all mobile phones. It allows the subscribers to send short-length text messages to other subscribers. The concept of SMS was introduced by Matte MacKinnon, a Finnish civil servant. Though most people understand what the SMS is, but only a few know how it actually functions.

The SMS or text messaging transmissions are first sent to the SMSC (Short Messages Service Center) from where they are further relayed to the recipient of the message. In case the recipient does not receive the SMS on the first attempt due to any reason, the SMSC will try to send it again. The number of time the SMSC will try varied with the service providers.

The text messages are transmitted through the SS7 within the standard framework of GSM MAP. These messages have particular payload strength; and a 140 byte signaling protocol. This means that all SMS have a constrained character limit. Therefore, a new language has been developed for the SMS called ‘txt speak’. This is the practice of reducing the length of words as well as phrase so that the required number of words can fit into the allowed bandwidth. The text messaging software charges also vary from country to country, and also with each service provider.

With the advancement of technology, it is also being predicted that SMS services will allow transmission of more data and will also be a lot more reliable.