Thursday, April 22, 2010

The cost of texting

What price do you put on having people who love you as close as your pocket, anywhere, anytime?
Given such measures are hard to calculate, what is the 'true' or financial cost of a text message?
Please do check the maths, the dashboard isnt up with the digital play, and maths is not my strong point...however the bit calculator has helped

A standard SMS message contains up to a maximum of 160 characters.
Most messages are way shorter than this,but I will work with the standard charge as people are charged for the potential not what is actual.

Apparently SMS uses 7 - not 8 - bit characters - and it is 1 bit to 8 bytes, except when its SMS and then its 7 normally...
1120bits divided by 7 gives the 160 characters that can be used in a message

At the maximum, of 160 characters, that would be a transfer of 1120 bits of data and converting this to Bytes...
140 bytes

And using my online converter this is
0.13671875 Kb

The costing in NZ has been 20 cents a message sent, regardless of whether it is one character at 7 bits or 160 characters at 1120 bits.
Admittedly there are a variety of other costing options now available (2010)
with telecom
and vodafone
and 2degree mobile (newcomer with a significantly lowered transaction cost, not used by the majority of cell phone users so i have not yet factored these costs)

And regardless of the number of bits sent, we are charged at the maximum possible, used or not, 140 bytes of message being sent each time.

So, 140 bytes divided by the cost per message gives us 140/20 so,
every 7 bytes of data sent by mobile SMS costs a NZ 0.01 cent.

I'm told by the people I interview for my PhD research that young people use texting because it's cheap, but I am now wondering if the actual costs are cheap.
How does texting compare then with other media transfer costs?

The cost of a song to my ipod...
2500Kb to 6000Kb per song and a song would cost me 99cents per song from apple.
If I take nice little songs with nice round numbers, say 4MB or 4000Kb or 40,000 bytes of data. Then that song is going to cost me- from apple-
404 bytes of data costs a NZ 0.01 cent.

And then to download it on my NZ$67.00 a month plan for 10 gigabytes
(10 gigabytes is 10485760 Kb or 10737418240 bytes or 85899345920 bits)
(Nb. this also gives me a web page posting, but note how expensive broadband access is for NZers...yet it is soooo much cheaper than sending a text message)

10737418240 bytes can be be divided by my monthly broadband charge of $67.00
to work out the NZ$1.00 charge per byte, so,
160259974 bytes per NZ$1.00
and divided by 100 cents in the dollar, gives me
1602599.74 bytes to the NZ 0.01 cent.

Now I'm not a maths savvy person, so feel free to correct this if I am wrong

for 1 cent 'apple' can sell me 404 bytes of access to a song
for 1 cent I get 1602599.74 bytes of data downloaded when I'm on my computer
and 1 cent gets me 7 bytes when I am sending a cell phone message
23,000 times more expensive to text on a mobile phone than data transfer by computer

It is more than a little unfair to compare 'apples with oranges' as I don't have any 'need' for a song, but I might have 'need' for contact.

So comparing texting with other forms of communication:

A letter. How much does that cost me?
NZ $0.50c, for 500gms standard post.
This would be unfair, taking three days to arrive isn't really a fair contrast.
Within 24 hours fast post, NZ$1.00 per 500gm.
A more reasonable contrast, however, I do note that convenience is compromised, but maybe being able to say so much and even send pictures could be used to balance the equation a little.
A sheet of paper weighs about 4.5 grams...and I need to allow for an I could easily send 100 pages...and I can write, or draw, on both sides!
When I'm teaching students essay writing, I assume a rough count of 250 words a page...average word is 5 characters, add one character for space per word...and font size still has to be reasonable...and I can send 250 words per page x2 as its double sided...
So that is 500 words a page x 100 pages
50,000 words for NZ $1.00
Or 500 words per cent (not that this is possible, because i will be charged the minimum NZ$1.00 postage)

And 500 words per page (double sided) times 6 (average letters per word and a gap per word), times 100 for the number of pages I can send plus the weight of an envelope...
Then 500x6x100 = 300,000 bits can be sent
And if I take the 'bit' charge per character as 7, since that is what SMS messaging works on... then
300,000 bits could be sent for NZ$1.00
30,000 bits for NZ 0.01 cent.

To convert bits to bytes...
1024 bits to the byte...1 bit = 8 bytes usually -except in the case of text its 7 -
1 bit 7 bytes
30,000 bits x 7 = 3750 bytes or 3.662109375 Kb

Bear in mind, I should subtract the costs of these pieces of paper, and of the ink, but at present i will stick with the transaction cost...

so 1 cent to apple can sell me 404 bytes of access to a song for as long as i want it
for 1 cent I get 14925 bytes of data downloaded when I'm on my computer
and 1 cent gets me 3750 bytes of mail delivery
and 1 cent gets me 7 bytes when I am sending a cell phone message

Amazing then that texting is bought as a cheap option...
"fast, (almost) free, and easy"
'Cheapness' is a relative concept, it is what's perceived.
It also involves issues of convenience, and of relative comparisons.
Being able to 'do it' and 'do it now' has enormous appeal.
The costs of a phone call are higher. The start up costs for a computer vs mobile are higher. The monthly cost with a server is higher- albeit that it gives me greater service potential. The time and transaction needed for sending a letter is longer and more convoluted.
My mobile is as close as my pocket, but I am paying significantly for convenience.

This blog was prompted by today's sideswipe article
True cost of texting:

"According to Nigel Bannister, a scientist at the University of Leicester, sending a text message can be up to four times more expensive than downloading the same amount of data from the Hubble Space Telescope."

Which traces back to a 2008 article

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