For quite some time now, I have been wondering about the popularity of SMS text messaging. Since its development by the GSM working group in the mid 80s and the initial launch to the generic public when the first SMS message was sent in 1993, SMS text messaging became the most widely used form of data communication in the world, with about 2 and a half billion users (that’s about half of the world’s population). How is it possible that such a limited technology could have become this widespread?
There are of course some obvious advantages to the basic application of text messaging, but there are also a lot of technical limitations in the SMS protocol as well as some strange implementations by telecom operators and handset manufacturers, that very much limit the usability for the users. Let’s have a look at some of them.
Advantages of SMS text messaging:
- Very easy to explain
Even the most technophobic cell phone user is able to grab the idea of text messaging. The message you enter on one handset will appear on the display of the receiving handset. The only thing you need is the receiving party’s phone number. There is no need to know anything else, such as an alternative address other than the cell phone number, or knowing the capabillities of the receiving handset or the services of the telecom operator.
- 100% installed base of handsets
SMS is supported on all GSM handsets (the only cell phone standard in Europe, and the dominant standard worldwide), and nowadays also on handsets of competing technologies. SMS sending and receiving is supported by all mobile carriers and offered trough all mobile phone plans. Everybody who owns a mobile phone is able to send and receive text messages. No need for additional devices, no need for special subsciptions.
- No action required to receive messages
An SMS text message will always appear automatically on the handset’s display. There is no need to “request” for incoming messages. When the phone was off during the initial transmission of the message, it will be delivered within minutes after the phone is turned back on.
As explained above, the concept of SMS text messaging is easy to understand, which undoubtly contributed to its huge popularity. Sadly, some pretty odd decisions were made during the development process of the SMS specification, which truly limit the usage of text messaging up until today.
Limitations of the SMS text messaging protocol:
- Limited length
For various technical reasons, mostly to compromise on cost in both the setup of the mobile network and the software and hardware in the phone handset, the lenght of an SMS text message was fixed on 140 bytes. Due to the use of 7 bit characters in the western alphabet, this results in 160 characters per message. When other alphabets are used that need 16 bit Unicode (Greek, Russian, Japanese, etc.), the lenght is even further shortened to 70 characters. (Multi-part messages even cut into this per-message limit by eliminating a further 7 characters, needed within the system to assemble the messages in the right order.)
- No group chat
Messaging is only possible between 2 users. Some handsets offer the possibility to send the same message to multiple receipients, however there is no way for the receiving party to determine to which people the message was addressed, prohibiting a “group discussion”.
- No re-retrieval of messages
Once the message is delivered to the handset, it is no longer stored by the Message Center on the mobile operator’s network. This means that the message can never be re-sent to the user in case the handset was erased or the messages it stored were otherwise lost.
- No device-independent reading of messages
A message can only be sent to a mobile phone number, which is always assigned to a specific cell phone. When a user has two cell phones in use at the same time (for example a private phone and a corporate phone), he is unable to retreive the messages on the other phone. When a user has no access to his phone for some reason, there is no way to read the SMS message sent to him on other devices either, like on a (public) computer.
Besides these obvious disadvantages, there are some other limiting factors in the way SMS text messaging is implemented by most telecom operators and handset manufacturers, but which are not specifically related to the SMS specification.
Limitations of the general implementation of SMS text messaging:
- Very high costs
For mobile phone operators, SMS text messaging became the cash cow of their services. Pricing ranges from a few cents up until 10, 20 or even more cents per message. Measured in terms of “cost per megabyte”, SMS text messaging is by far the most expensive data communication protocol currently available.
- Even higher roaming costs
In Europe, expensive data roaming costs kick in as soon as you pass the borders of telecom operator’s native country. Operators charge up to 5 times as much for sending a text message abroad, compared to the local fees. (Roaming does not apply to the various states within the US, however most American operators have the habit to charge for incoming text messages as well, which is not the case in Europe.)
- Limited message storage space
Most handsets traditionally offer a limited space for the storage of messages. Since most basic handsets offer no possibilities to transfer these message to a computer as a form of a backing up, and operators can not re-send messages that were delivered before, this requires selective deletion of messages by the user, and eventually the loss of messages.
- Extremely un-intuitive user interface
Most basic cell phones only offer a numerical keypad and a small display, which means that the user is required to perform text entry using 9 numerical keys (!). To me personally, having to enter 26+ different letters and symbols by using only 9 keys is a demonstration of the worst possible user experience possible. Some handsets offer a form of predictive text entry, but this still requires a great deal of attention of the user on accepting, denying and modifying the suggestions offered by the handset.
I have often wondered why, instead of using a dedicated message develivery mechanism based on cell phone numbers, the creators of the SMS text messaging protocol have not relied on e-mail based addressing instead. This would of course eleminate the first advantage that I mentioned above, in that every cell phone user is reachable for text messaging by just using their cell phone number. However, I think the advantages would have clearly outpaced this disadvantage, such as unlimited message length, the possibility to add other documents such as pictures, the possibility to read the messages on other e-mail capable devices, the capability to communicate between more than 2 people and the ability to re-retreive lost messages from the e-mail server. But I do recon the fact that when SMS was being developed (in the mid 80s), its creators were faced with the technology limitations of that time (which were mainly related to the high cost of sending data over the network, and the high cost of storing data on an electronic device).
The biggest problem with SMS as we know it today, is that it was developed about 10 years too early. Surely, a lot of the limitations of the SMS specification would not have been there if the whole specification would have been written today. Sadly however, with an installed based of more than 2 billion users as stated above, there is no way the specification can be changed now without breaking compatibility.
In the spirit of this blog’s core interest, let’s have a look at how SMS is implemented on the iPhone. I think Apple solved as many of its shortcomings as possible. For starters, it eliminates the ackward 9-key text entry method by replacing it with a full Qwerty-keyboard on its touch display, with a pretty smart auto-correction method built in. Due to the fact that predictions are not based on the entry using 9 keys, but on the placement of (independent) letter keys relative to each other, a much more intelligent correction system could be developed. And furthermore, as the basic application of SMS texting is sending short messages to one person and vice versa, often resulting in “mini-conversations” between the two users, the iPhone logically orders the sent and received messages per user. Oddly, most cell phones just place all the incoming messages in chronological order in an “inbox”, and put the sent messages in an “outbox”. This completely eliminates the possibiity to see an ongoing conversation between you and someone else, without doing a lot of back-and-forth navigation on the phone.
Also of note are some specific choices and trade-offs that Apple made in its SMS application on the iPhone. For starters, it does not display the number of characters left when entering a text message. Whether this is the result of negotiations with the cell phone carriers (because, after all, this more easily results in the user sending more than one 160-character message resulting in higher revenue for the operator), or an eastetical choice based on limiting the number of “status feedback” on the display, is anyone’s guess. I know that some users would welcome the ability to having a character-couter though.
A very clear choice that Apple made is to not include an MMS application. MMS (Multimedia Messaging Service) is an addition to the SMS standard, which, albeit the fact that the technology is now over 5 years old, is not quite as common and popular as SMS. Using MMS, users can send pictures taken with the phone’s camera to other cell phone users capable of receiving MMS messages. The iPhone can neither send, not receive those messages. I think Apple made a deliberate choice here. The iPhone’s built-in e-mail client is far superior to anything else on a phone, and supports rich messages, including pictures. This allows for users to send messages with text and pictures to other users via e-mail, and hence eleminates a lot of the limitations of MMS. Of those, the very high costs and, again, a message size limitation resulting in scaled down, low resolution images are the most obvious. And like SMS, MMS is also device and phone number dependend, limiting users from accessing the message and the pictures on other devices but their phones. I guess that, as long as the market is not crying out fool for an MMS application on the iPhone, Apple hopes that at least for rich messaging, we use the obvious, cheap and feature rich platform that has proven itself for decades: e-mail.