Why Text Messages Are Limited To 160 Characters

The LA Times has a story about Friedhelm Hillebrand, one of the communications researchers behind efforts to standardize various cell phone technologies. In particular, he worked out the 160 character limit for text messages. "Hillebrand sat at his typewriter, tapping out random sentences and questions on a sheet of paper. As he went along, Hillebrand counted the number of letters, numbers, punctuation marks and spaces on the page. Each blurb ran on for a line or two and nearly always clocked in under 160 characters. That became Hillebrand's magic number ... Looking for a data pipeline that would fit these micro messages, Hillebrand came up with the idea to harness a secondary radio channel that already existed on mobile networks. This smaller data lane had been used only to alert a cellphone about reception strength and to supply it with bits of information regarding incoming calls. ... Initially, Hillebrand's team could fit only 128 characters into that space, but that didn't seem like nearly enough. With a little tweaking and a decision to cut down the set of possible letters, numbers and symbols that the system could represent, they squeezed out room for another 32 characters.

Comments

I'll Be Damned

[eldavojohn]

And all this time I was almost certain that it was based on sound scientific research proving that 160 characters was the maximum amount of text a cell phone user could read before completely losing interest.

Re:I'll Be Damned

[Anonymous Coward]

Technically, it was the largest number that Hillebrand could count to in his mind before losing track.

Re:I'll Be Damned

[JeffSpudrinski]

The few times I've tried messaging from my cell phone, my thumbs cramp after about 50 characters, so the "limitation" never affects me.

Re:I'll Be Damned

[Red Flayer]

tl;dr

Re:I'll Be Damned

[Anonymous Coward]

And all this time I was almost certain that it was based on sound scientific research proving that 160 characters was the maximum amount of text a cell phone us...

I totally lost interest past that.

Re:I'll Be Damned

[BrokenHalo]

You might want to make two posts next time. Character count with space = 208.

Don't start me. I know any number of supposedly intelligent people who are apparently incapable of reading a simple email containing a series of questions or points.

They will respond to the first question, but anything after that is consigned to /dev/null. I occasionally get cranky about it and send off a series of single-sentence emails, with the query in the sentence line.

I don't know whether it's my circle of acquaintances, but the worst offenders seem to be MBAs. (Maybe it really does mean Master of Bugger-All). Or maybe it's just the Simpsonisation of society that gives it the attention span of a flea.

Re:I'll Be Damned

[omnichad]

I don't get your point. All I read was "I don't get your point. All I read was: "And all this time I was almost certain that it was based on sound scientific research proving that 160 characters was t"

Re:I'll Be Damned

[nlawalker]

This may be my number one pet peeve when it comes to professional communication. I have tried a number of ways of getting multiple questions to register, but nothing seems to be perfectly effective. The best tactic I've managed to come up with is including only the following in the body of an email:

1. A preamble, no longer than two sentences, that says something along the lines of "[Person's name here], I need your response to the following questions by [date]:". Using their name is key, even if no one else is on the To: or CC: line.
2. A *numbered* list of questions (not bulleted), each ending in a question mark.

The other thing I've started doing is keeping a running list called "waiting on" that serves the sole purpose of listing the responses and tasks I'm waiting on from other people, no matter how small. As a consultant, I've found that "due diligence" means "one reminder email at least every other work day" when it comes to getting questions answered. Otherwise, getting chewed out for not adequately following up is a very real possibility. I've been asked for a paper trail before, and I always get a laugh of approval when I spool out the reams of email I've sent trying to get the simplest questions answered.

Re:I'll Be Damned

[bennomatic]

You're totally right.

• people respond somewhat well to bullet lists
• people respond somewhat well to numbered lists
• give people a paragraph or two and they will either ignore it, or worse, call you.

Re:I'll Be Damned

[MrMarket]

Have you tried picking up the phone. You can always send your e-mail (but with the answers) as a paper trail of your conversation.

It provides two benefits:

1) Developing relationships. It's amazing how far a few seconds of idle chat can go to put a human side to your interactions with the people you need things from. This is really important with gatekeepers.

2) Forces you to be concise: If you have 30 seconds to ask for something - you'll be forced to get to the point more quickly.

If you don't get them, don't leave a vm. Just send your e-mail and call them later.

Re:I'll Be Damned

[FatdogHaiku]

If you make it into a MySpace style survey (mix in questions about favorite color and second letter of last name, etc.), not only will they answer you, they will forward it to everyone they know... and most of those people will also reply.

Re:I'll Be Damned

[nomorecwrd]

Actually, SMS is like a "stowaway" of a signal your cell must receive from time to time.
So the "real" cost of a SMS is 0.000000.

This is a broadly known fact.

Years ago, here in Chile anyway, SMS where free of charge.
Now is pure profit. (about 8ct/SMS at current exchange)

Re:I'll Be Damned

[Urkki]

Actually, SMS is like a "stowaway" of a signal your cell must receive from time to time.
So the "real" cost of a SMS is 0.000000.

This is a broadly known fact.

Just like the "real" cost of a phone call is also practically zero for the operator, as the extra electricity used for one call is basically nothing. So every call charged by minute is pure profit for the operator.

Which is (partly) why there are packages with a lot of free minutes and messages. At least in Finland, for around 50 eur / month you can even have unlimited audio and video calls, unlimited SMS and MMS messages and unlimited 3G data.

Re:I'll Be Damned

[theaveng]

>>>The cost is zero to the telcos, but the profit is gravy. It is a complete rip-off scam to the consumer.

I disagree. The retail cost is whatever the market will bear. This idea goes all the way back to John Smith, and is not necessarily tied to the actual cost of the good. You might call it a "ripoff" but it's a ripoff that customers *voluntarily* enter into. They could just as easily decide not to do texting (as I do).

The flip-side of this is that money collected from all these texters helps subsidize my (and your) voice calls. I pay just 18 cents a minute, which is a real bargain considering wired phone calls in 1990 used to be 25 cents a minute. Simple inflation says the price should have increased to 45 cents, but instead prices have dropped and with the added benefit of being wireless. Without texting the voice calls would have to be significantly higher in order to cover the maintenance/electricity costs.

Anyway it could be worse.
The cellphone company could be run by Congress (like Amtrak).
In which case you wouldn't have a choice;
instead they'd suck the money from your paycheck.

With today's private companies I can choose to buy or not buy, text or not text, make calls or not make calls. I control my own destiny and how much I want to spend (or not spend).

Re:I'll Be Damned

[Mr2001]

I disagree. The retail cost is whatever the market will bear. This idea goes all the way back to John Smith, and is not necessarily tied to the actual cost of the good.

I think you mean Adam Smith, and I think you're misreading the GP. Cost != price. The retail price is whatever the market will bear, but the cost of providing SMS service is virtually zero.

You might call it a "ripoff" but it's a ripoff that customers *voluntarily* enter into. They could just as easily decide not to do texting (as I do).

It's awfully glib to say we shouldn't be upset about being ripped off just because we have a choice. In a free market, with healthy competition, the price of goods and services should fall to just above their actual cost. That obviously isn't happening with SMS: customers would like to pay less, but no one is offering SMS for less, even though it costs almost nothing to provide. Doesn't that suggest a market failure?

Anyway it could be worse.
The cellphone company could be run by Congress (like Amtrak).
In which case you wouldn't have a choice;
instead they'd suck the money from your paycheck.

Or perhaps it could be run like the US Postal Service, in which case it would provide world-class service at a far lower price than any of its competitors. The USPS will carry a physical envelope from my doorstep to someone else's doorstep, thousands of miles away, for less than the price of 3 text messages.

(I'm not saying we should nationalize cellular companies - just pointing out that services set up by the government aren't inherently inefficient as you seem to be implying.)

no, its because 160

[circletimessquare]

is the bastard offspring of the union of the hexdecimal and the decimal, literally 16*10

all of us techies straddle these two worlds. 160 is our numerology of frustration, the techie 666

Re:no, its because 160

[Anonymous Coward]

it also happens to be precisely 2 lines of text on a good old 80 character wide terminal.

Re:no, its because 160

[SgtPepperKSU]

is the bastard offspring of the union of the hexdecimal and the decimal, literally 0xF*10

fixed that for you

Are you joking?
0x10*10...

Re:no, its because 160

[jellomizer]

80 characters (bytes) just happened to be how many punched you can normally fit on a standard punch card.

Why text messages instead of email?

[loshwomp]

The real question should be "Why are we still using ancient text messages instead of regular email?" All of my friends in Japan regularly do full-on email on their phones, and only have a vague-if-any notion of what a regular "text message" is elsewhere. 160-character limit? That is *so* 1990s.

Re:Why text messages instead of email?

[Krneki]

Because you can charge for SMS, while emails needs full Internet access. And they don't want to give us cheap Internet access.

Re:Why text messages instead of email?

[Sockatume]

The account's set up with your phone number, uses the same user identifier, travels with the phone number, and there's a billing infrastructure for it. Meanwhile the vast majority of phone users don't even have packet data plans. It's operator inertia, basically.

Re:Why text messages instead of email?

[Speare]

I think the Japanese and Chinese markets have completely ignored the SMS thing because of the character sets involved. If 160 latin characters can be compressed into about 128 bytes, how many hanzi can fit? Maybe forty? That's probably enough for some thoughts like "Meet you at train station at 11am" but nothing really more complicated than that.

Re:Why text messages instead of email?

[FredFredrickson]

I laughed a little when I read your comment. Stupid USA, no internet on their cell phones! Get with the times.

It occured to me shortly after, that I don't have internet on my cell phone either. A sad truth.

Interestingly, quite a few companies all have a vested interest in keeping society from progress. I mean, just a few articles back, we had an example of the newspaper industry just not getting it. My gut feeling? Wouldn't it make sense, instead of a billion different newsbook-readers, each for it's own brand of newspaper, just let me get my news on the cell phone?

And suddenly I see the problem- we don't have internet on our phones because NOBODY wants us to have the access that snuck up on US companies.

Corporations wildly mis-underestimated how the internet would take off. Instead of investing in it then, or learning from their mistakes, they're not investing in it now. So we still have companies fighting the internet. Even the internet companies are fighting us having internet.

Too late though, cat's out of the bag, and once you've seen it, you can never go back. I will never settle for a dumbed-down version of the internet, and going back to buying CDs (I buy mp3s) and purchasing cable (I watch hulu, and rent netflix).

Once we ALL have email on our internet enabled phones, we won't be able to be charged for each txt message. The internet is a pipeline, we can use email, IM, twitter, or whatever we please to communicate. This will be the undoing of the txt addons in the same way internet TV has/will ruin subscription cable.

Re:Why text messages instead of email?

[Lumpy]

Because the packet data plans are insanely overpriced!

In the usa it's all about raping the consumer.

Re:Why text messages instead of email?

[julesh]

If 160 latin characters can be compressed into about 128 bytes, how many hanzi can fit? Maybe forty?

Probably more like 64; two bytes is usually enough to represent just about anything. A clever encoding scheme might squeeze as many as 80 in. OTOH, each of those characters carries more information than a single character of English text. Not sure about Japanese, but most common Chinese words are only two characters long, so being able to include fewer characters shouldn't be a real issue.

Re:Why text messages instead of email?

[Aladrin]

128, at least, assuming UTF8. And the Japanese can say things a lot more compactly than we can:

èããY - I woke up.
åå¾OEãé£Yãã¾ã--ãY - I ate in the afternoon.
éf½éYã®åé"ãé話ã'ã--ã¾ã(TM) - I am talking on the telephone with my friend in Tokyo.

(Of course, the above won't come through correctly on Slashdot, but they are about half the characters of the English phrases.)

Re:Why text messages instead of email?

[IgnoramusMaximus]

(Of course, the above won't come through correctly on Slashdot, but they are about half the characters of the English phrases.)

I could never figure out why the main Slashdot site garbles all 2-byte character sets, since clearly the Slashcode itself can handle it.

SMS vs email

[pieterh]

An exercise in cartel economics: compare the costs of SMS traffic vs. email traffic and explain the differences. :-)

Re:SMS vs email

[Rob Kaper]

Differences:

- SMS is available: it's built-in, e-mail is not present on every phone and relies on a third-party service provider plus settings

- SMS is faster: because there is no GPRS/TCP/IP/SMTP/IMAP/POP connection and transfer overhead

- SMS is clean: no risk of having to retrieve large attachements, hardly any spam due to sender costs

- SMS is cheaper: most plans offer a sufficient amount of free messages a month for most users, e-mail requires an additional GPRS data plan

YMMV but SMS is not as bad as some people claim.

Re:SMS vs email

[Dan East]

Here's what's ridiculous. I have a Blackberry, and do not have an SMS plan with my carrier, thus each text costs me 25 cents to send. Receiving SMS is free and unlimited. I have an unlimited data plan for Blackberry, so I simply send emails using the carrier email SMS gateways for "free". The only downside is that the recipient cannot directly reply to my message. Here's the stupid part. The amount of bandwidth, processing, and inter-service gateways my emails have to pass through must require at least 100 times the resources of sending an actual SMS. The final kicker is that even if I keep my actual message under 160 chars, they are usually broken up into more than one SMS message because of the header attached by the SMS gateway that contains my email address, etc.

No need for more

[XPeter]

bc whn u txt u typ lik ths so ther isnt any ned fr mor thn 160 chars. I'm a teen, I know best.

Bad article

[Sockatume]

The article states outright that the 160-character limit came before Hillebrand's "typewriter experiment", and that the experiment actually about because of an argument between Hillebrand and a coworker about whether 160 characters was sufficient for a sensible message. This meshes with what we already know about SMS, namely that it could never have been much more than 128 characters for technical reasons. Quite why the article structures its opening to suggest that Hillebrand pulled the number out of his arse after some typewriter time is a mystery.

Getting 160 chars in 128 bits.

[pavon]

For those that were wondering how they got 160 characters into 128 bytes (6.4 bits/char), they didn't. The increased the length of the frame to 140 bytes, which is is 160 characters using a 7 bits/char. Curiosity forced me to look this up, expecting to find some snazzy compacting algorithm for a non power-of-two alphabet.

Re:Getting 160 chars in 128 bits.

[evanbd]

There are some straightforward compaction algorithms for non power-of-two sizes. The simplest approach is to take n symbols in your alphabet, treat it as an n-digit number base b (the number of different symbols), and convert that to base two. You'll use at most ceiling(n * log2(b)) bits.

You can be more sophisticated by using a compression algorithm of some sort (Huffman with a standardized dictionary, for a simple example). Anything that does better than the above n * log2(b) will produce a variable length output, though, which means that while you could usually fit more than 160 characters into 140 bytes, sometimes the limit would be lower (since rare characters take more bits to encode).

BINGO!

[wonkavader]

And a full-screen terminal (3270, etc.) is really just 25 punch cards. You press "Enter" and they get submitted. Your batch processes and the system returns you 25 punch cards which your smart 3270 punch card reader/editor displays for you.

Punch cards are based on the civil-war-era dollar bill because there were already machine to count and stack dollar bills.

Punch cards were IBM's most profitable product ever until the introduction of the IBM PC.

Re:BINGO!

[OlRickDawson]

http://en.wikipedia.org/wiki/Punched_card Punch cards predate the computer, because they were used in loom machines to generate paterns. The punch cards were later used for statistical purposes. IBM was already selling statistical machines that used the punch cards before the computer. The reason that IBM was able to grab the market instead of Univac, is because IBM's computers was compatible with the punch cards that the corporations already had.

Re:BINGO!

[plover]

I wonder what type of DRM you can put on a punch card

You could print shadowed boxes that look like punched holes, that way if someone puts them on a photocopier or in a fax machine it'll look like the holes are there, but a real reader wouldn't see them.

You could put transparent tape over a few of the holes. The common cheap, at-home card readers which read cards optically to save a few bucks will not notice the transparent window. But the Big Iron IBM punch card readers that use real steel fingers to read the holes will simply ignore the taped-over holes.

Along the same vein, you could put red colored tape over the holes, and build the Genuine IBM readers with blue laser readers instead of red. They'll be transparent to the at-home punch-card copy machines that use cheap red lasers, but opaque to the blue frequencies.

Or you could punch some extra or oversized holes in some non-standard locations, like the old half-tracks on the floppy disks. Only official IBM punch machines would be able to accurately copy them.

I got it! Embed a smart chip in the corner of each JCL card, with some cryptographic verification or signature algorithm. As each punch card travels through the system, electrical contacts would verify the authenticity of the card. 4096-bit RSA on the chip ought to do the trick nicely.

Silly me.

[hrimhari]

Here I was, in my dumb ignorance caused by blind experience on the field, thinking that the limit was actually caused by the magic 255 number less protocol overhead (result: 140) plus 7-bit encoding compression (result: 160).

In 2009

[Tarlus]

And all these years later in 2009, I still have

Re:In 2009

[Tarlus]

to cut my message in half before I can send them.

Step-parent of the year.

[jcr]

My 17 yr old (mostly stupid) step-daughter

That remark gives me a far more negative opinion of you than of her.

-jcr

Re:Step-parent of the year.

[jcr]

Actually, I find the honesty refreshing.

Actually, excusing bad behavior as "honesty" is something I'm rather tired of. Disparaging his wife's child like that shows me that he's someone lacking in empathy or compassion.

-jcr