How much is SMS?

I just discovered that AT&T (A-pay & pay?) Reduced the cost of text messaging. When I first connected to AT&T 6 or so years ago, the cost of sending SMS was 10 cents, receiving was completely free.

When AT&T switched to Cingular, the cost of sending a message fell to 5 cents, but they began to charge 5 cents for the incoming text. Considering that you reply with a message to each message received, the result is the same amount as before.

AT&T came back and gradually phased out the Cingular brand, and prices changed again. This time it became 15 cents in both directions.

More changes have been made than I can recall. On the one hand, text messages were 10 cents in both directions, and on the other hand, they even included MMS (multimedia messages) for the same price as SMS.

In March, SMS messages at AT&T will cost 20 cents and MMS - 30 cents on both sides: sending and receiving.

So, let's do some calculations and find out how much this simple data transfer actually costs.

A standard SMS message contains up to 140 bytes (1120 bits) of data - this allows you to send messages up to 160 characters in length. At first, this may not be clear, until you realize that SMS uses 7 rather than 8 bit encoding, leaving you with only 128 possible characters instead of normal 256. So, 1120 bits / 7 bits = 160 characters .

The total length of our message is about a tenth of a kilobyte (.13671875 Kb). In terms understandable to the iPod generation: if you had an iPod with only a tenth of a kilobyte of memory, you could fit 1/4000 songs in it. Hereafter, I assume that 1 song = 4 megabytes.

If you divide 140 (the number of bytes available to you) by 20 (price per message), you will find that you pay 1 cent for every 7 bytes of data. It turns out that you pay $ 1,497.97 for 1024Kb contained in 1 megabyte. IPod users: it will cost you $ 5.991.88 to download, not even purchase, just a song via SMS.

For comparison, I pay $ 50 per month for a non-stressful limit of 500 GB through my ISP. In total, 512,000 MB or 10,240 MB per dollar comes out. This allows me to download 2,560 songs for the same money that a Junior Bacon cheeseburger costs on Wendy’s menu: $ 1. I will use this my standard measurement later in the article.

I can make the following statements regarding the cost of the band:

The cost of downloading 2,560 songs:

From my provider: $ 1
Via SMS: $ 15,339,212.80

Wait, it seems more here!

When calculating the cost of SMS, most people do not take into account that the message is actually paid twice! If I send a message to another AT&T user, I pay for sending And they pay for the reception! It must not be legal, but that's another matter.

So how much does SMS actually cost? Not 20 cents - 40! This increases all my numbers obtained above.

Moreover, my calculations suggest that people actually use all 160 characters available to them. Say, on average, people use only half of the possible number of characters (at best), then the price of data again doubles.

After adjusting these two statements, we found out that our number obtained above is not at all close to the real result. Fixed, the comparison looks more like this:

Download price 2,560 MP3:

Through my Internet provider: 1 $
Via SMS: 61,356,851.20 $

Wow! Here are the best data! Not surprisingly, SMS exchange alone is an industry of $ 100 billion a year!

"How great is that? Get Hollywood movie revenue from all ticket offices around the world. Add revenue to the global music industry. And add revenue from all video games around the world. And even putting all this together, we will not get 100 billion. "

Let's improve the results even further - how much can hand-delivered data cost?

The US Postal Service charges 41 cents for this privilege (hmm ... only one cent more than AT&T charges for automatic SMS delivery). So how much written information could we convey in a letter?

Google says that the page can accommodate 250 standard words, and the paper page weighs about 4.5 grams. The US Postal Service allows you to send letters weighing up to 1 ounce without changing the delivery price, this is about 28 grams. So you could send 6 paper pages, minus 1 envelope. If you write on both sides, you will receive 2500 words (10 pages x 250 words).

Corresponding to this page, the average length of an English word is 5 characters. Add spaces for each word and get 6 characters per word or 1,500 characters per page, with a total of 15,000 characters.

Now we are not limited to the type of characters that we can use, but let's assume that we are using a 256 character (8 bit) set.

Therefore, our letter gives us 14 Kb for 41 cents. To transfer MP3 using this method, we need about $ 119.95. To transfer 2,560 MP3 it is necessary to spend only 307,072 $. It is also necessary to take into account the overall thickness, but to clarify our purpose (and because I do not feel able to calculate it), let's leave it as it is.

The price will be greatly reduced if we put the data on, say, a DVD, and our price will be something around $ 1.20.

We will update our calculations above:

Shipping cost 2,560 MP3:

TCP / IP: 1 $
TCP / SMS: $ 61,356,851.20
TCP / USPS : $ 307,072.00 (bits written on paper)

It turns out that delivering SMS byte by byte is 200 times more expensive than delivering a message “to your hands” to your doorstep anywhere in the United States.

What justification can explain why SMS messages are 61 million times more expensive than data transmission from an Internet service provider and 200 times more expensive than TCP / USPS? How is technology, communication and infrastructure getting cheaper, and the price of SMS is growing exponentially? My theory: SMS messages are transmitted through the golden air.

Editorial: Several readers indicated that the title implies that it is about the internal cost of sending SMS. Therefore, we will listen to what a more informed Slashdot user says:

“ I know the real cost of SMS!

I made a report at the university a few years ago. The marginal cost of SMS is 0.

They really have a small cost / opportunity. In fact, SMS messages are sent through the control channel. Initially, SMS was developed in the GSM standard as a control system. Just like the ICMP protocol in the IP stack. Then NOKIA introduced the real instant messaging feature using SMS. A control channel is a channel through which your mobile waits for notification of incoming calls. So, to receive SMS sent a control signal. Since the bandwidth of the channel is somehow limited, it is possible that in a situation of mass exchange (use) of text messages, the control channel will clog and the normal audio protocol will stop working. To prevent this, at the moment, providers are using something like QoS, which delays SMSs while there is a risk of congestion. So,

Another story for MMS approx. Their cost / ability is equally low, since they almost completely go through GPRS, using the maximum channel. Thus, MMS with pictures, music, and possibly video MUST cost less than SMS.

So you are surprised why I pay so much for SMS or MMS or even Call: after paying all debts for the initial infrastructure paid by the operator, you still pay due to market segmentation (you can’t change the connection on the fly) and a little for monopoly (it is also impossible to start a new connection from 0). "