How much is SMS?

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



When AT & T switched to Cingular, the cost of sending a message dropped to 5 cents, but they began to take 5 cents for incoming text. Considering that you are replying with a message to each received message, then in the end, the same amount came out as before.

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AT & T has come back and gradually rolled up the Cingular brand, and prices have changed again. This time it was 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 to AT & T will cost 20 cents and MMS - 30 cents in both directions: sending and receiving.



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



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 it may not be clear, as long as you are not aware that SMS uses 7, not 8-bit encoding, leaving you only 128 possible characters instead of normal 256. So 1120 bits / 7 bits = 160 characters .



The total length of our message is about the tenth kilobyte (.13671875 Kb). In terms understood by the iPod generation: if you had an iPod with only a tenth kilobyte of memory, you could fit 1/4000 songs in it. Hereinafter 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 for downloading, not even buying, just a song via SMS.



For comparison, I pay $ 50 per month for a non-stress limit of 500 GB through my Internet provider. Total goes 512,000 MB or 10.240 MB per dollar. This allows me to download 2,560 songs for the same money as a Junior Bacon cheeseburger on Wendy’s menu: $ 1. I will use this standard measure of mine further 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 is another question.



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



Moreover, my calculations assume that people actually use all the 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 that our number, obtained at the top, is not at all close to the real result. Corrected, 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! No wonder that just an SMS exchange is a $ 100 billion-a-year industry!



“ How great is that? Take revenues for Hollywood films from all ticket offices around the world. Add revenues to the global music industry. And add revenues from all video games around the world. And even putting it all together, we will not get 100 billion. "



Let's improve the results - how much can the delivery of data "in the hands" 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 price of delivery, it is about 28 grams. So you could send 6 paper pages, minus 1 envelope. If you write on both sides, you will get 2500 words (10 pages x 250 words).



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



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



Consequently, 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 goal (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, say, on a DVD, and our price will be something around $ 1.20



Let's update our calculations made above:



Shipping price 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 the delivery of SMS bytes per byte is 200 times more expensive than the delivery of the message "in hand" to your doorstep anywhere in the United States.



What excuse can explain why SMS messages are 61 million times more expensive than data transfer from an Internet provider and 200 times more expensive than TCP / USPS? How does technology, communication and infrastructure become cheaper, and the price of SMS increases exponentially? My theory: SMS messages are transmitted through the golden air.



edition: Several readers indicated that the headline implies that it is a matter of the internal cost of sending an SMS. Therefore, we will hear what the more informed user Slashdot says:



“ I know the real cost of SMS!



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



They really have a low cost / opportunity. In fact, SMS messages are sent through the control channel. Initially, SMS was developed in the GSM standard as a monitoring system. As well as the ICMP protocol in the IP stack. Then NOKIA introduced the real instant messaging feature using SMS. The control channel is the channel through which your mobile waits for incoming call notifications. So, to receive SMS, a control signal is sent. Since the channel's bandwidth is somehow limited, it is possible that in a situation of mass exchange (use) with text messages, the control channel will become clogged and the normal audio protocol will stop working. To prevent this, at the moment, providers use something like QoS that delays SMS while there is a risk of congestion. So, we can solemnly declare that the marginal cost is 0 and the cost / opportunity is also 0.



Another story for MMS is approx. Their cost / opportunity is equally low, as 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 the debts for the initial infrastructure paid by the operator, you still pay due to market segmentation (you cannot change the connection on the fly) and a little for monopoly (it is also impossible to start a new connection with 0). "