SMS or Short Message Service

SMS or Short Message Service is a telecommunications service for the transmission of text messages. With SMS gateways, additional services are connected. In this article we will discuss about the technical part well known SMS or Short Message Service.

Technology behind SMS or Short Message Service

SMS uses a signaling channel of the GSM standards such as SDCCH (Standalone Dedicated Control Channel) or FACCH (Fast Associated Control Channel). These channels are also used to build and maintain conversations. Text messages can be parallel to a telephone line to send / receive. For this purpose a part of the bandwidth of the traffic data is channelized temporarily to the signaling channel (SACCH) and reconfigured to send / receive a text message used.

The dispatch of such a SMS is always performed by a mobile phone short message service center ( SMSC ), usually the network operator, it is not sent directly from one phone to another. The number of the message center has the same structure as of a normal mobile phone number (MSISDN = Mobile Subscriber Integrated Services Digital Network Number), and the settings of the mobile device is stored. The message center reads the header from including the destination number and sends the SMS either in its own network to the destination number and sends it to the network operator of the destination number. The various operators are connected to each other. If the recipient has not a mobile device, but an application, the contents of the message over data connections to the server of the service provider is  passed.

The limitation to 160 characters in a SMS results from the maximum user data length of the MAP (Mobile Application Part) of the signaling system. This is for the transmission of short messages between the MSC and the SMSC used. SMS can be in different character encodings.

The use of even a 16-bit special character, such as letter with an accent or umlaut changes the coding scheme of an SMS and reduced its (partial) length to 70 character.

With over a long text messages, known as Multi-SMS (concatenated SMS, long SMS) is used for longer texts and sent  as individually divided and settled as a rule, each individual part as a separate SMS. The receiver (if capable) then set the pieces back together into a coherent SMS as part of the full text.

Other points on SMS or Short Message Service

In most Countries, SMS is treated to have at least some legal value when evaluated inside the premise of Court of Law. Silent SMS indicates neither it is displayed nor creates an acoustic signal. When mobile operators, fall on call data, the user identification used in particularly by the police to locate people or for the creation of entire motion profiles. So other than Communication SMS does have legal implications as well.