DSL Speed query

It boils down to a difference of scale. Network communications are done in a base 8 system, while computers use a base 2 system. So, there's some math required to convert them to like units so that they can be directly compared. Of course you don't need that complicated formula, you just take the Kbps speed and divide it by 10. It's not perfect, but it's a quick and easy way to get a good ballpark figure for max theoretical speeds, accounting for overhead. And as you'll see, you get nearly identical figures.

So what it says, is that a 1.5Mbps DSL connection should be able to download at a max speed of around 150K/s. Of course there are a whole host of things that can drag that figure down. The biggest one, is that computer networks are kind of like a highway. It makes no difference if you're driving a Ferrari or a Pinto if there's a traffic jam that's slowing traffic to 25mph.

Any overloaded router between you and the server you're trying to get data from can cause speeds to drop dramatically. You should try to find a speed test server that is as close to you physically as possible, so as to minimize the number of hops required. Ideally your ISP will have their own bandwidth test server, so you can get a much more accurate figure. If you consistently get speeds well below what you're paying for, then call up your ISP and/or phone company, and have them come out and check the lines. Also make sure you're using the DSL filters on all other phone jacks being used, just NOT the one connecting to the DSL modem.

And the difference is important, but not everyone in the tech/computer business talks using the same measurements. There is also, unfortunately, confusion when tech people talk in "K's". For some it is 1000's, but for others it is 1024's.

A bit is a binary digit, and it is the smallest piece of data that can be stored or transmitted. So one bit of data is one item of data, and 4 bits of data are 4 items of data. In an electrical circuit, (which is all that computers and the internet are), a bit is either the presence or the absence of an electrical current, that is, the current is on, (1 bit), or off, (0 bits).

This is useful because it fits into binary arithmetic where 0 and 1 are the only digits that are used. For example, a stream of 5 bits of data may look like this; 10011, (that would be a pulse of electricity, then no pulse, then no pulse again, then a pulse, and finally another pulse of electricity. The receiver times the expected message and if no pulse is received in the alloted time that is treated as a 0).

A Byte is 8 bits of data. Bits are signified by the small b and Bytes are signified by the capital B.

So if you have 16 bps, that means you have 16 bits per second. However, that also means you have 2 Bps, or 2 Bytes per second. (16 divided by 8 = 2).

Where you see K is confusing. In decimal maths K would signify 1000, but in binary K would be used as 1024, (2^10 where 2 is the basis of binary arithmetic). Marketing people prefer to use K = 1000 because it is easier to understand.

That means that, if you have 56 Kbps, that means you have 56 x 1000 bits per second, (the usual speed of a dial-up modem), or 56,000 bps. Notice how I am now using K as thousands, but not as 1024's. But if you divide that by 8 for Bytes, you only get 7000 Bps, or 7KBps.

When dial-up internet connections were the norm, this caused immense confusion and frustration. A person would believe he was getting 56 KBps, because he saw 56 Kbps on the package, and the marketeers did not explain the difference between B and b. He was only getting 7 KBps.

When checking their speed at internet speed check sites, they were told they were getting 7 KBps, and not 56 KBps, because those sites used the Bytes measurements and not the bits measurement.

Nowadays broadband is becoming more available, but the same confusion arises. In your case we would need to know exactly what you were on before and what you are getting now. 512 k and 1500 k doesn't mean much without knowing whether it is 512KBps or 512Kbps, and similarly with 1500.

If you were on 512Kbps before that would be the same as 64KBps, and 1500 Kbps now would be 187.5 KBps, (divide each by .

Your speed test results seem pretty good. 627.7kbps and on another day I got 535.1kbps. These are 78.5 KBps and 66.9 KBPs respectively. However, as Jackson says, the speed of your connection is not the only factor. If you are in an area where a lot of people are using your ISP's broadband connection then your speed will decrease. It's like a motorway or highway. The potential for high speed is there, but if all the lanes in front of you are busy and the traffic is slow, then your own speed will be slow as well.

So in your case you may have the potential for 1500 Kbps, but internet traffic may be slowing that down somewhat. It is a sad fact that the more people who sign up for broadband, the slower it will become eventually. But against that, 627.5 and 535.1 Kbps is really very good.

I hope this helps. It is very complicated, so let me know any part that you can't quite understand,

Mark