Technical Info

Types of Mobile Messaging

  • Text Messages
  • Smart Messaging
  • Message Service
  • Multimedia Messages
  • Email

Each type of message is described below.

Text Messages:
TM (Text messages) is the simplest and most common type of text message and is supported by a large number of mobile phones. It typically allows for text messages with a maximum of 160 characters per message.
Technical note: The 160 character maximum applies to messages written in English and some Western European languages, which can be represented by 7-bits per character. For other languages including some Eastern European languages, Middle Eastern languages and Asian languages which require 8- or 16-bits per character, this maximum is reduced to 140 characters and 80 characters respectively. Also note that some mobile phones allow you to create "concatenated messages" which actually can extend the maximum number of characters.

Smart Messaging
Smart Messaging was developed by Nokia and is found only on Nokia phones. Smart Messaging allows Nokia phone users to create messages that have pictures, ring tones, virtual business cards and other types of non-text data, all within a message that is roughly compatible with the text standard. In other words, although these messages may contain non-text content, they still use text data stream to communicate the data.
The great thing about Smart Messaging is that it allows people to do simple picture messaging, but with the low cost, quick message transmission and high simplicity of regular text messages. By "low cost", we mean that Smart Messages do not cost the mobile phone user any more money to send than a regular text message, and they can be sent in roughly the same amount of time as text messages. By "high simplicity", we mean that the user interface in the telephone makes creating Smart Messages very easy.

Message Service
The Message Service standard was a collaborative effort of Alcatel, Motorola, Siemens and Sony/Ericsson, and this standard emerged as a response to Nokia's proprietary Smart Messaging standard. Since it was developed after Smart Messaging, and since it involved the collaboration of several manufacturers, this standard is better thought out, more flexible and easier to support.
This allows for pictures, animations, ring tones, and other non-text content similar to Smart Messaging, but in addition, it adds the ability to format the text messages including the font size, font color, font style (bold, italics, etc.) and text and picture placement within a message.
Like Smart Messaging, the great thing about those messages is that they use the text data stream for transmission, thus providing the low cost, quick message transmission, and high simplicity of text messages.

Multimedia Messages
The standard Multimedia Messages includes the ability to create messages with text, picture, music and other content. multimedia messages may consist of multiple pages, each page with its own text, picture, music, etc.
standard multimedia messages protocol is the newest and most complicated standard currently employed by mobile phones. Because it is so new, this opens the door to incompatibility between phone manufacturers and even between mobile carriers (i.e. the implementation and use by AT&T may not be equivalent to the implementation and use by Verizon, Alltel, etc.). Because of this, there may be "interoperability" issues between mobile carriers and between mobile phone models.
One clear and easy-to-understand difference is the picture resolution supported by camera-phones. Some camera-phones allow for relatively low-resolution pictures such as 352 by 288 pixels while others support 640 by 480 or higher. When a picture is sent from one phone model to another, it must be converted for proper display. This conversion is done by "trans-coders" at the mobile carrier. This trans-coder process currently works pretty well within a given mobile carrier but may not work at all across mobile carriers.
There is another downside of the proticol and that is the size of the data and speed of data transmission. Obviously with high resolution color pictures, the size of the message is much larger than simple text messages (tens or hundreds of kilobytes as opposed to only 256 bytes). As a result, standard multimedia picture messages take longer to send and receive. While a typical mobile phone might be able to receive 20 text messages per minute, that same mobile phone may only be able to receive a single standard multimedia protocol picture message per minute. And since the amount of data is greater, mobile operators charge a much higher fee per message sent and received. While a text message may cost only a few cents to send or receive, multimedia picture messages may cost 20 cents or more. In any event, clearly this is the next generation of mobile data and thus one which will continue to grow in popularity.

Email originated on personal computers, as a method of sending text communications over the internet. As mobile phones have evolved, many newer models now include the capability to send and receive email. In fact, when composing a picture message with a mobile phone, most will offer the ability to send this picture message to an email address as well as to a phone number).
Email can often be a good alternative to sending a standard multimedia message since it offers a user the same ability to send messages with text and pictures. For those with a mobile phone, the advantage is that sending a picture message to an email address may require less data communications and thus, it can be faster to send an email than to send a multimedia message. Also, many mobile plans include sending email for free, but have a charge associated with sending a multimedia message.
The disadvantage is that it can be more tedious to spell out an email address using the keypad on standard mobile phones, because you must triple-tap the letters to spell the email address. In some parts of the world, such as Japan, email is the defacto method of sending text communication between phones.

How Long is a Text Message
A single part message is somewhere between 67 and 160 characters, depending.

Standard Text Messages
Standard Text Messages are limited to 140 bytes. You can encode 160 7 bit characters in 140 bytes. Trouble is, even if you are only using simple ASCII characters you're not guaranteed it will fit. That's because is encoded in GSM 03.38, not ASCII.
Some characters require two characters to encode. For example ^, €, ~, [, ] and some others. Send a message consisting only of '~'s and you'll find you're limited to 80 characters. Send a message that you've carefully limited to 160 characters, but include a single '~' and you now need two messages to send it.
With Unicode, for languages such as Chinese, Russian etc, and you're restricted to just 70 characters per standard text message.
70, not 80 as 16 bytes are needed for encoding each character.

Multipart or Concatenated Text Messages
In order to send long multi-part messages, each part needs some additional information to ensure the receiver can assemble the parts correctly. This needs a message ID, a part number and the total number of parts. In order to do this, 6 bytes of each message is now devoted to the User Data Header (UDH), which contains the ID and part information for the message.
This now leaves 134 bytes (or 153 characters) for the actual message.
Yet again we have to take account of the characters that require two characters to encode so we're now looking at potentially 67 characters for Unicode languages, or escaped characters.

GSM encoding:
1 standard text message = up to 160 characters
2 concatenated text messages = up to 306 characters
3 concatenated text messages = up to 459 characters
4 concatenated text messages = up to 612 characters
5 concatenated text messages = up to 765 characters
through to
9 concatenated text messages = up to 1,377 characters

UTF-8 encoding:
1 standard text message = up to 70 characters
2 concatenated text messages = up to 134 characters
3 concatenated text messages = up to 201 characters
4 concatenated text messages = up to 268 characters
5 concatenated text messages = up to 335 characters
through to
9 concatenated text messages = up to 603 characters

What "Message and Data Rates may Apply" means
Cell phone carriers' rates are based on the services they provide. High cost plans are usually all inclusive - unlimited texting (messages), for example. Budget plans which usually cost less than $20/month, may give unlimited nationwide calling, but every other service has a limit. Budget plans charge you for more than a minimal usage. High cost plans offer unlimited usage. You can go to the main menu for your cell phone, usually one screen to the left of the home screen, and scroll down to Data or Data Sense and you can pre-set it to the amount your plan allows so you don't go over it and add on charges to your monthly bill.
Below you can find some examples of high rated message texts and how to avoid them.

Unwanted Premium Rate Texts
Also known as 'reverse billed' messages, premium rate texts come from four, five or six-digit numbers and are normally for subscription services such as games or weather updates.
You might not realise you're being charged, and can mean you end up with a shockingly high phone bill.
Texts of this kind can only be sent out if you sign up to the service.
There are several scenarios where you should check the small print before you sign up to a text service, so you know exactly what it will cost.

Be careful Sharing your Phone Number
Unfortunately a lot of people subscribe to premium-rate texts by mistake. For example, by failing to tick or untick a box on a website or replying to a message.
This means you should be even more careful when entering competitions or registering for a service.
Think of your phone like your credit card - if you give out your number, you could be charged.
Unless you're really confident you know how a website will use your number, don’t enter it online.

Quizzes, prizes or competitions
Something that claims you could 'win a new tablet or phone' may seem tempting but it may not be all it promises to be.
When you come across adverts claiming you can win prizes, make sure you read the small print before entering.

Installing apps
Some mobile apps including games can send text messages from your phone to a premium rate number.
Before you click download make sure you check what the app really does.
Don’t download apps from non-trusted app stores and always check the list of ‘app permissions’ before you download.

Using short text message numbers
Mobile marketing text messages often come from short numbers.
Texting to these shorter mobile numbers - called mobile shortcodes - can cost more.
These numbers are often used to pay for new features in apps, to donate to charity, to enter competitions and to download games.
You may see these numbers in promotions asking you to text a certain word to a number or, you may receive promotional texts asking you to reply to them.
Be aware that if you do text these numbers, you may be charged a premium and you may also be signing up to unwanted text messages, premium or otherwise.