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Hacker movies from the early Nineties have one thing in common: the ubiquitous, nerve-jangling screech of a modem connecting to the internet. From back then until fairly recently, using a modem has been how most of us have connected to the internet ─ a frustrating process involving fiddling with ‘phone cables, waiting as the modem sounds change and hoping that the little “Connecting….” sign eventually disappears. Thankfully, things have changed now and broadband technologies like ADSL (Asymmetric Digital Subscriber Line) have made the process of connecting to the internet much easier, faster… and a whole lot quieter.
Strictly speaking, broadband refers to anything that uses a wider range or “band” of frequencies than other similar technologies. The term broadband, however, most often refers to a connection medium that is faster than dial-up. There are several new emerging broadband technologies, divided into those that are “wired” (i.e. require a cable) and “wireless” (those that don’t). Broadband wired technologies currently include:
Broadband wireless technologies include:
Not all technologies will be available in all locations, for example, in South Africa there is no cable TV infrastructure and, therefore, there is no cable modem service. ADSL broadband is currently the most widespread of wired broadband technologies in South Africa.
While there is a vast difference in the underlying technology that is used for dial-up as opposed to ADSL, the principle differences relate to how you use it. The first major difference is that you cannot make a phone call while using a dial-up internet connection. A dial-up connection physically makes a phone call over the telephone line to a similar modem at your ISP. The telephone line is thus fully occupied and cannot be used to make or receive telephone calls as long the dial-up connection is active. Should you need to use the telephone line for a telephone call, the active dial-up connection will need to be disconnected. Hence the term “dial-up” is used, as each time a connection is required the modem “dials” over the telephone line to make the connection. Anyone needing to contact you while you are connected will just get the busy signal. On the other hand, the ADSL broadband connection exists outside of the basic function of the telephone. Once connected to the ADSL network, the ADSL link will remain permanently active. Your telephone can therefore be used as normal without interfering with or interference from the ADSL connection. There is no need to keep connecting to the ADSL network on an ad hoc basis as is required with a dial-up connection. The other major difference is the speed. Since dial-up works in the same frequency band that is used for transmitting voice, there is, therefore, a limitation on the speed of data that can be transmitted over a dial-up line. The fastest a dial-up connection can reach is 56 kbps download and 48 kbps upload. Since ADSL uses a higher frequency band, and has more frequency available, the line speed is much faster and can reach speeds of up to 24 Mbps download, which is 500 times faster than that of a dial-up connection. When you switch from dial-up to ADSL, you will wonder why you didn’t do it sooner!
ADSL broadband will make surfing the internet or connecting to your network an always-on, faster and more exhilarating experience. Not only that, it’s provided at a fixed monthly cost, saving you money on telephone calls. How do you save money? Well, if you are a dial-up subscriber and connect to the internet for an hour and a half during an average working day, you can easily spend over R800 per month on internet access:
Now, compare that with the cost of a typical 3GB ADSL account:
Note: These above costs are directly related to the internet access services and do not include ancillary costs, such as telephone line rental and the cost of a modem or PC. Connecting to the internet for only 1.5 hours a day during the week on a dial-up connection could cost you R171 more per month than an ADSL line. Call costs can quickly get out of control, and staying connected to the internet for 8 hours a day on a dial-up connection could cost as much as R3,800.00. It is clear from the above example that ADSL is more cost effective for even moderate use of the internet. However, more importantly, ADSL is broadband and broadband is fun! With ADSL broadband you enjoy:
Get the ultimate in internet and business experience from an ADSL line!
There are two questions to ask:
Firstly, let’s look at the capacity you will need from your ADSL line. Here we refer to the size or speed of the ADSL line. It is critical that you choose the correct size for your line in order to ensure that you get the best performance out of your ADSL service. Currently, there are three options available as seen in the table below:
The bigger the ADSL broadband line speed, the faster your access to the internet will be. The question you need to ask yourself is, “what am I using the ADSL line for?” Is it for home use, business use or will it be shared by many people on a Local Area Network (LAN)? Once you know the answer, you can start to work out the ADSL line speed you require. Let’s look at an example of the time taken to download a 700 MB Linux installation CD, highlighted in the table below. The trade-off is that the bigger the line speed, the higher the cost.
Next, you need to determine which internet service to get. This is a network service that is required over and above the physical ADSL line and is sold by ‘cap’ size, with the cap sold in a number of Gigabytes (GB). The available offerings will include capped accounts from 1GB up to a massive 30GB. The GB value relates to the total number of bytes you can transfer over the ADSL link in a month before the service is either severely throttled or cut off completely. Using the above example, you can only download the Linux installation CD one and half times with a 1GB capped account before you will reach your limit. Pricing also scales up as you buy an account with a bigger cap. It is a similar decision to the line speed decision, however, the parameters are different. You may not necessarily need a fast ADSL line, but if you are sending numerous e-mails with attachments, this could quickly deplete a small 1GB cap. Most ISPs allow you to top up or change your account if you find that you are reaching your cap before the month is out. This allows you to manage your ADSL service better and find the optimal pricing point that best suits your ADSL needs. Another point to consider is what else is bundled with an ADSL service:
Security and the internet have become synonymous, and for good reason. Any computer that is connected to the internet is under threat of being compromised by some form of malicious attempt to gain control of the computer. ADSL is no different to any other connection medium in this regard, and all the necessary precautions need to be taken. This includes:
Another security concern is that of data interception once the data has left the firewall and is travelling over the actual ADSL line. You can secure your local connection as much as possible, but once data leaves that LAN and moves over the internet, it is susceptible to interception. This could be done using a ‘packet sniffer’ on a compromised machine somewhere on the ADSL network, or simply connecting to the telephone wire outside your premises and scanning the packets as they travel along the telephone line. The only way to make certain that your data will be 100 percent secure is to encrypt it. This is why banking and other secure online web sites use SSL encryption. Another aspect of security that is often overlooked is the wireless component. A lot of ADSL routers have Wi-Fi access points built into the device. This is a potential risk if the Wi-Fi access point is not secured. It is a simple process to secure an access point to prevent unauthorised access to the Wi-Fi access point, but most of the available ADSL routers and modems have an unsecured default configuration that poses a potential risk if it is not changed.
A standard ADSL service will give you basic connectivity into a data network, usually the internet. While this is the primary purpose of an ADSL line, there are additional value-added services that can make your ADSL service experience better and more useful:
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