SMS, or Short Message Service, is
emerging as a multibillion dollar a year industry. A leading research firm
that consumer spending on mobile services represents a $140 billion opportunity worldwide, with
SMS making up half of that. Portio Research
that there were 946 billion SMSs sent in 2006. Clearly, the medium has hit the mainstream.
Reach and mobility are SMSs most powerful draws. There are 2.41 billion SMS-ready handsets in the world today, enough for a third of the world's population. In fact, some 30
more than one
phone per person
As for mobility,
a cell phone can go, a text message can go. This gives you, the service or application developer, the opportunity to deeply integrate your features into daily life. Coupled with the fact that it is a true push technology, this means that all types of information can be delivered to people wherever they are, exactly when it's most meaningful or useful.
Creating your own SMS service can be quite simple, as there are a number of different implementation options suitable to a variety of needs and circumstances. This guide will describe several of them to help you pick the option most appropriate to your needs.
However, there is more to building a successful SMS service than implementing code that sends and receives text messages. SMS
a different set of opportunities and constraints relative to a traditional browser-based web service or desktop client application. The 160 character limit is the most obvious limit, and the "Always On Everywhere" nature of the mobile phone the most obvious opportunity, but there are a host of other less apparent factors to consider when designing your service.
So, beyond describing the mechanics of creating a SMS service, this guide seeks to describe the art of creating a
> Message Format
Chapter 1. Introducing SMS
An SMS is a message delivered to or from a mobile phone. In the industry, messages originating from a phone are referred to as MO (mobile originated) or MT (mobile
). As author or operator of a service that employs SMS, you don't need to know a lot about the specific protocols and
use to send these messages, but there are aspects of the format that may impact your use.
1.1. Message Format
A text message is limited to 140 bytes, or 160 7-bit characters. If you are sending Arabic, Korean, or other languages that require 16-bit encoding, you will be limited to 70
It's possible to send 8-bit characters, but they are not typically viewable on phones (they are used instead for data such as ringtones and over the air provisioning of WAP settings). Additional information, such as the sender's number and the time stamp, are included as well, but are not counted against the 160 character limit.
MMS, or Multimedia Message Service, is an evolution of the SMS system that allows users to send photos,
, and audio in addition to text. Unlike an SMS, there is no set limit on text length, either. Instead of being sent on the GSM signaling channel, MMSs are sent over an IP connection from an MMS-C to the phone. The IP connection to an MMS-C must always be initiated from the phone, however, a carrier will typically send an SMS to the phone that contains instructions for the phone to connect back to an MMS-C via IP to collect the MMS message.
The system for sending and receiving MMS messages is quite different from SMS, and varies somewhat by carrier, so it won't be covered in this guide.