 Our focus so far has been on ADSL as the most dominating technology that comes from the DSL family. Indeed it is the most widely deployed but at the same time because of certain unique user requirements coming from some end users, some corporations and some enterprises we need to provide some kind of variation in the kind of asymmetry and data rate provisioning if it can be done through DSL. We'll see how that is done and then we'd look at comparison table of these technologies. So DSL is a complete suite or a family of technologies. The choice actually depends on what the user exactly wants. Most of the users are quite comfortable with the provisioning of ADSL. But sometimes in certain applications as we earlier mentioned voice over IP, Skype, interactive, gaming, etc. certain asymmetric services are then required. And then there is a very unique requirement in terms of distance from the central office or exchange as well. You might have heard it from your service provider that in your neighborhood DSL technology, ADSL as such is not provided or cannot be provided because your neighborhood is a little farther from the exchange. So it means that if at all some service has to be provided for internet connectivity then how longer distances can be achieved by bringing some kind of modification to the DSL. Here in this table, we'd have a look at the different DSL technologies in terms of their data rate upstream and downstream it is important. Of course, we look at these. Another important aspect is how much distance is allowed or is permissible from the central office. That is what is the maximum length of the local loop or the access side. Then the number of lines that can be configured or that are actually needed then does a certain variant of DSL coexist with the telephone network. Usually, I mean, if we just look at ADSL, we expect that if ADSL can then every variant of DSL should but it may not necessarily be true. Now let's look at each of these one by one. Let's start with the ADSL, the one that we have amply covered. We have a downstream data rate of 8 megabits per second upstream of one. Compare this with the high bitrate DSL. High bitrate DSL may sound high but in terms of data rate, it is only limited to 1.54 megabits per second which is the T1, the transmission 1 standard for US and Japan. But HDSL is, if you might have already noticed, it is highly symmetric. The maximum length that it can cover is around 3.65 kilometers but it needs two telephone lines to provide symmetry in real sense and it cannot exist simultaneously with the telephone line if the telephone calls are to be made. Then we have the multirate symmetric DSL. It allows a choice to get multiple variable data rates that can be obtained in a symmetric manner. The distance here can go very long. It's around 8,800 meters, that's around 9 kilometers. Again, it cannot share the line with the telephone call. Other interesting variants are the rate adaptive DSL. Here the asymmetry is huge. You see we have 7 megabits per second on the downstream and only 1 megabits per second on the upstream. Then we have the symmetric DSL, the absolutely symmetric and the very high data rate DSL which is very impressive. You see for shorter distance if the local loop is limited to around only a kilometer that is 1200 meters up to 52 megabits per second on the downstream and 16 megabits per second on the upstream can be achieved while the telephone calls can also be successfully made. Now it means that if you are fortunate enough to live in such close proximity to your central office or the exchange you can probably subscribe to VDSL as well.