DSL FAQs
Introduction to DSL
Digital Subscriber Line (DSL) technology provides high-speed Internet Access using regular telephone lines. It has the ability to move data over the phone lines typically at speeds from 256K to 1.5Mb - up to 25 times quicker than the fastest analog modems available today (56,000 bits per second).
- What are the benefits?
- Are there different types of DSL?
- How fast is it?
- How can it be so much faster than a modem when it uses the same phone line?
- How does it work?
- Will it constantly connect near the maximum speed, or will it be like my 56K modem that almost never connects at 56K?
- What is the difference between ADSL and cable modems?
- Can DSL be shared among two or more PCs, so that both can be connected to the internet at the same time?
- What about my email? Will I have to change my email address?
- What is involved with Installation?
- What computer equipment do I need?
- Is DSL available everywhere?
- How can I find out if my location qualifies for DSL service?
- Are there any specific phone line qualifications to getting DSL?
- How long does it take to get DSL service?
- DSL is Always On, 24 hrs A Day
- No Dial-Up Required
- Data Security
- No Second Phone Line Required
- Use the Phone At The Same Time You Are Online
- No Dropped Connections
- Super Fast Speeds
- Flat Rate Billing
- Upgrade Speed As Your Needs Change
- Cost Effective
- The Bandwidth You Need To Truly Experience The Internet
In addition to its very high speed, DSL has many benefits over analog connections. Unlike dial-up connections that require analog modems to "dial-in" to the Internet Service Provider every time the user wants to retrieve email or obtain access to the Internet, DSL connections are always on. That means no more logging on and off, no more busy signals and no more waiting for the connection to happen - it's always there! Another benefit is the ability to use the telephone at the same time you're accessing the Internet; you don't have to choose between the two.
Are there different types of DSL?
There are two main types of DSL. The most popular and cost effective type is Asynchronous Digital Subscriber Line (ADSL). It is called "asymmetric" because more bandwidth is reserved for receiving data than for sending data. Download speeds range from 256 Kilobits per second up to 1.5 Megabits per second, and upload speeds range from 128Kilobits to 384 Kilobits. This model works well with Internet related activities. The requests that you make to the internet are usually a few keystrokes while the resulting response is a graphically rich web page or streaming video or even file or music downloads.
Another type of DSL is Synchronous Digital Subscriber Line (SDSL). With this type of DSL the up and down load speeds are the same. This service more closely matches dedicated circuit (T1) service levels and more expensive prices. SDSL is not as widely deployed and doesn't carry the same standards as ADSL but would be a good option for businesses that are doing webhosting or heavy online business where the files sizes in and out are large.
NTD Athenet provides ADSL service.
Depending on the level of service you choose, the ADSL modem can download data at speeds ranging from 256 Kilobits per second up to 1.5 Megabits per second. This speed is more than 25 times faster than a 56.6 Kbps modem. As with all Internet related activity, the speed that you experience may be impacted by the capacity of your ISP (NTD Athenet has redundant T3's to the internet - a lot of bandwidth), the capacity of the system or web site that you are connecting to and/or the overall traffic on the Internet. For example traffic on the internet was substantially heavier near the 9-11 events than previous to that time.
How can it be so much faster than a modem when it uses the same phone line?
Analog modems send their signals through the public switched telephone network, the same one that connects ordinary telephones. ADSL modems "piggyback" their signals on top of the voice signal. On the phone company's premises, the line gets split - the voice calls are sent to the public switched telephone network, and the data transmission goes to the Internet. This method moves data off the phone companies' lines and instead uses connections optimized for carrying Internet traffic.
ADSL works by splitting the phone line into two frequency ranges. The frequencies below 4 kHz are reserved for voice, and the range above that is used for data. This makes it possible to use the line for phone calls and data network access at the same time.
Will it constantly connect near the maximum speed, or will it be like my 56K modem that almost never connects at 56K?
At ADSL speeds, the limitations are much more the performance of the Internet server you're trying to reach and the amount of traffic on the Internet. The Internet is a loosely coupled network of computers that are transmitting data by different methods through different computers at different speeds, so the speed you receive data with an ADSL modem is limited by these factors.
What is the difference between ADSL and cable modems?
ADSL provides always-on high-speed Internet access over a single dedicated telephone line; cable modems offer always-on high-speed Internet access over a shared cable television line. While cable modems have the potential for greater downstream (from the Internet into the home) bandwidth capabilities, that bandwidth is shared among all users in a neighborhood, and will therefore vary, perhaps dramatically, as more users in a neighborhood get online at the same time. Cable modem upstream (from the home to the Internet) traffic will in many cases be slower than ADSL, either because the particular cable modem is inherently slower, or because too many people in a neighborhood are trying to send or receive data at the same time.
Can DSL be shared among two or more PCs, so that both can be connected to the internet at the same time?
Yes. If the modem or router has one, or multiple Ethernet 10baseT interfaced, it can connect an entire LAN. That way, all users on the LAN can share the higher connected bandwidth. If the modem has only one 10baseT interface, you can connect it to a mini-Ethernet hub which will distribute the bandwidth over a LAN. In the case of business networks a router is typically deployed to provide Network Address Translation, dial backup services and other features like VPN and Firewall.
What about my email? Will I have to change my email address?
That depends on whether the company that is currently providing your email account also provides ADSL service. Web-based email clients, like Netscape's Webmail or Hotmail, will not be affected by a change to ADSL service. If you are an NTD Athenet dial-up client already, your email address will not change.
What is involved with Installation?
Briefly, residential DSL service requires a DSL modem that connects to your computer via a standard USB port or 10-BASE-T Ethernet network interface card (NIC). Business accounts with multiple users and computers would use a specialized DSL router.
In some cases you may have the choice to either install the service yourself using the simple self-installation kit, or have the service provider come out and install it. In either case, NTD Athenet can provide the approved equipment for all standard connections.
What computer equipment do I need?
Most reasonably current home computers can connect with DSL with little or no problems. NTD Athenet's DSL service works with Windows PC and Macintosh computers. Windows versions should be Win 98, ME, 2000 or XP. Most common DSL modems use the USB port found on most computers. If the USB port is not present or available, an Ethernet Network Interface Card (NIC) would be installed in the computer and an external DSL modem would attach to it. NTD Athenet can provide all the needed equipment.
DSL was engineered to use the same copper wiring that your phone lines use, so in general, the only availability limitation for DSL is the distance limitation from your location to the phone company central office (CO). This distance limitation is calculated in "wire feet", i.e., the length of the actual wire from the CO to your location, which may be different than the linear distance. The distance limitation typically is in the 18,000 wire foot range. There are other issues that may factor in to this limitation. Some phone lines have "load coils" on them that make them unsuitable for DSL at any speed or wire distance.
Another limitation may be the presence of an Subscriber Loop Carrier (SLC) in the service area. An SLC (sometimes called a "slick hut" because it typically is a small brick building) is a distribution point from the phone company to a neighborhood or subdivision. If the SLC hut is equipped with the correct equipment, homes or offices in that area may be able to get DSL with a new distance limitation starting at the SLC facility.
How can I find out if my location qualifies for DSL service?
A quick call to the NTD Athenet Sales Staff at 920-954-9799 will allow them to verify your phone number or address for service.
Are there any specific phone line qualifications to getting DSL?
For NTD Athenet's DSL service you must have:
- "Non-Centrex, Ameritech telephone line
- "No alarm, e.g. burglar, associated with the phone line to be used for DSL
How long does it take to get DSL service?
Most installations are done in 10 to 15 business days. NTD Athenet will provide a 56k dial up account for you to use at no charge until your circuit and hardware are installed.