Thursday, July 31, 2008

The TeXTing Swindle

I recently started communicating with some family via "texting", because, for reasons I don't fully understand, they will happily respond to a text message (and send them out on their own), but won't answer a regular phone.

So ignoring the annoyance of trying to draft up a message on the toy 10 key keypad on my phone -- which takes approximately 20 times as long as it would to say the same thing in a voice call, I started thinking about the economics behind the texting fad.

My provider charges me $0.20 per text message. My overlimit minutes cost about $0.25. (Picture messages cost more -- $1.95 each, I think.)

This is the biggest swindle made by phone companies in recent history.

Look at the data involved.

A phone call (voice message) takes the following bit of bandwidth:

  • Assume 8-bit ULAW or ALAW sampling (12 bits compressed to 8 bits)
  • Assume 8 kHz sampling, which is typical for "phone quality" audio
That gives up 8 * 8000 = 64,000 bits per second or 3,840,000 bits per minute

Now, consider a typical text message. Say 12 lines at 40 characters each. (That's more than my phone will display), each character at 8 bits (we'll assume ASCII for now, I can't imagine trying to conjure up CJK characters on my phone!), gives me 12 * 40 * 8 = 3,840 bits. (I didn't try to make the numbers work out as evenly as they do for this example, it just happened!) So, 3840 bits per message.

To a rough approximation a text message costs about the same to the consumer as a minute of talk time. HOWEVER, the bandwidth involved is approximately 1/1000. If everyone is texting instead of using the voice service, the service provider should have about 1,000 times more capacity!

Put another way, text bits are about 1,000 times more expensive to end user!

Now, consider pictures. $1.95 is nearly 10x the cost of a text message or a minute of talk time.

A fully decompressed 16-bit VGA (640x480) resolution picture takes about 4.9Mbits.

To a rough approximation, a picture takes about as much bandwidth as a minute of talk time. The picture is therefore 100x less expensive per bit to send than a text message, and about 10x more expensive than a voice call.

Of course the secret here is that texting is incredibly efficient use of bandwidth to send a message (compared to a voice call), especially with those wacky abbreviations (such as "c u l8r"), but the end user doesn't realize that it is costing the provider far less to send the same message via a text message. (Put another way, the end user has no idea how much network bandwidth is simply wasted with traditional voice calls.)

The mobile providers here have made a real swindle. The fact that they aren't trying to undercut each other on the text messaging does allude rather strongly to "collusion" in market pricing on them -- there should be a lot more competitive pressure to drive the cost of texting down, or even to offer it for free (especially with plans that have unlimited voice, such as mine).

In fact, the phone company should be begging me to use texting instead of voice calls, instead of charging me extra for texting.

Anyone from the mobile companies want to explain how you can get away with this swindle?

Ask your mobile provider why they aren't giving you texting for free with your unlimited voice plan!


Aredridel said...

Why? Because they can. But you knew that already.

And why do I do it? Because I like asynchrony. Also, because people don't know how to shut up and they're a lot easier to ignore in text.

Mike said...

Perhaps I missed it, but it seems your bandwidth calculations only consider the payload. There is a significant amount of overhead in call setup and tear down for each message. The shorter the message the greater the overhead as a percentage of the whole bandwidth used. Depending on the codec and if the protocol is VoIP or not, text messages could use up to twice the bandwidth of a call containing teh same number of voice payload bytes (that wouldn't be more than a hiccup).
All this does not however change my belief that the big 4 telecom giants are not seriously reaming texters.

Garrett D'Amore said...

True enough, Mike, I omitted protocol overhead.

Even if the protocol overhead doubles every text message, and voice data protocol overhead is zero (which it isn't), you still have a 500x overcharge for texting.

These days most telcos offer inexpensive add-ons for texting (typically $5 or so) that give up to unlimited text messages.

But its still a swindle. From the bandwidth calculations, Telcos should be practically begging us to use texting -- it should be free with any mobile package, even the most basic plans. Of course, that would make it harder for them to sell those extra minute plans....

Me, I hate texting, and I hate people who refuse to answer a regular phone call or dial me up and speak to me. But then again, I also use e-mail.

I guess I'm just a crotchety old fart who believes in the value of the spoken language and the written vowel.