DSL Internet Access Service
How Does DSL Internet Access Work?: Learn about the differences between traditional telephone services "POTS", and DSL.
Different Types of DSL: Understanding the different types of DSL services.
DSL Facts: Important information you should know about DSL.
Applications: What can DSL Internet Access do to help my applications run better?
Installing DSL: Here are some basic guidelines provided by the telephone company for installing and maintaining a DSL connection at your home or business.
DSL FAQs: Some common questions and answers about DSL services.
How Does DSL Work?
Traditional phone service, sometimes referred to as "Plain Old Telephone Service" (POTS), connects your home or small business to a telephone company office via copper wires. These wires are wound around each other in "twisted pairs". This enables you to exchange voice information with other phone users. The type of signal used for this kind of transmission is called analog. An input device, such as a phone set, takes an acoustic signal and converts it into an electrical equivalent in terms of volume and pitch. Since the telephone company's signaling is already set up for this analog wave transmission, it's easier to use that as the way to get information back and forth between your telephone and the telephone company. This is the reason why your computer must have a modem! The modem receives and translates the analog signal, and then converts the analog values into digital information.
Analog transmission only uses a small portion of the available amount of information that could be transmitted over copper wires. As a result, the maximum amount of data that you can receive using ordinary modems is only about 56 Kbps, a fraction of what is possible when using DSL. The ability of your computer to receive information is held back by the fact that the telephone company filters information that arrives as digital data, puts it into analog form for your telephone line, and requires your modem to change it back into digital. The result is slow down streaming.
So, you see, modern science came up with a technological solution to all this - DSL! DSL is a technology that assumes that digital data does not have to be changed into analog form and back. Digital data is transmitted to your computer directly as digital data. This allows the phone company to use a much wider bandwidth for transmitting it to you. The signal can be separated so that some of the bandwidth is used to transmit an analog signal; the result? You can talk on the phone and use the Internet on the same line, and do both things at the same time!
What's a Splitter? And Will I Need One?
A splitter is a frequency filter that separates the high frequencies used for sending data upstream and receiving downstream data from the low frequency range used for voice. These high and low frequencies are transmitted at the same time. Most DSL technologies now require that a splitter be installed at a home or business. So, generally the phone company has to make a visit to install it. And, of course, you've got to be home for the installation! It is, of course, worth the inconvenience and the small additional expense. However, with DSL Late now currently on the market, it is now possible to manage the splitting remotely from the telephone company's central office. This is known as "splitter less" DSL, "DSL Lite," G.Lite, or Universal ADSL, and has recently been made a standard. G Lite eliminates the POTS splitter, but still does require the installation of a small filter device next to every POTS device (telephone, fax, or modem) sharing the G. Lite line.
Different Types of DSL
Here's Some Very Useful Information on Each Type of DSL:
ADSL - Asymmetric Digital Subscriber Line (ADSL) is the form of DSL that is most familiar to home and small business users. ADSL is called "asymmetric" because most of its two-way bandwidth is devoted to the downstream direction, which sends data to the user. Only a small portion of bandwidth is available for up streaming (for sending user-interaction messages). Most Internet users, and especially those who use graphics- or multi-media intensive Web data, need lots of downstream bandwidth. For these applications, user requests and responses are small and require little upstream bandwidth. Using ADSL, up to 8 Mbps of data can be sent downstream and up to 640 Kbps are available for up streaming. The high downstream bandwidth means that your telephone line will be able to bring motion video, audio, and 3-D images to your computer or hooked-in TV set. And, more good news, a small portion of the downstream bandwidth can be devoted to voice, rather than data, so you can make phone calls without having to use another separate line.
- Delivers simultaneously high-speed data and POTS voice service over the same telephone line. Supports a range of speeds from 1.5 Mbps to 8 Mbps downstream and 64 Kbps to 640 Kbps upstream.
CDSL - Consumer DSL (CDSL) is somewhat slower than ADSL (1 Mbps downstream), but has the advantage that a "splitter" does not need to be installed.
G.Lite or DSL Lite - G.Lite (also known as DSL Lite, splitter less ADSL, and Universal ADSL) is a slower ADSL that does not require splitting of the line at the user end. G.Lite provides a data rate from 1.544 Mbps to 6 Mpbs downstream and from 128 Kbps to 384 Kbps upstream. In other words, it's faster than CDSL. G.Lite is expected to become the most widely installed form of DSL and the most sought after by home consumers.
- Supports POTS. A variant of ADSL based on the G.Lite standard for 1.5 Mbps downstream and 384 Kbps upstream. Intended for the mass market, including consumers, small businesses and remote offices.
HDSL - High bit-rate DSL (HDSL) is used for wideband digital transmission within a corporate site and between the telephone company and a customer. The main thing about HDSL is that it is symmetrical (up streaming and down streaming). For this reason, the maximum data rate is lower than for ADSL. HDSL can carry huge amounts of data, as is the case for T1 lines in North America. For this reason, it is the DSL service used for T1 lines.
- Supports symmetric service at 1.54 Mbps, but does not support POTS. HDSL is the DSL service already widely used for T1 lines. HDSL uses four wires (two pairs) instead of the new standard two wires used for other DSL flavors. A new version, HSDL-2, provides the same speed capabilities as HDSL, but uses only a single wire pair.
IDSL - IDSL (ISDN DSL) is actually closer to Integrated Services Digital Network (ISDN) (with data rates and service at 128 Kbps) than it is to the much higher rates of ADSL. It offers an "always-on" alternative to ISDN service and a data rate capacity of up to 144 Kbps.
- Offers an always-on alternative to dial-up ISDN service with a capacity up to144 Kbps.
RADSL - Rate-Adaptive DSL (RADSL) uses software to determine the rate at which signals can be transmitted on a given customer phone line. It adjusts the delivery rate accordingly. RADSL delivers from 640 Kbps to 2.2 Mbps downstream and from 272 Kbps to 1.088 Mbps upstream over an existing line.
SDSL - Single-Line DSL (SDSL) supports symmetric service. It is the same as HDSL with a single line carrying 1.544 Mbps each direction.
- Supports symmetric (downstream and upstream) services at 160 Kbps to 2.3 Mbps. SDSL does not support POTS connections.
UDSL - Unidirectional DSL (UDSL) is in the proposal stage. It's a unidirectional version of HDSL.
VDSL - Very High Data Rate DSL (VDSL) is a developing technology that promises huge data delivery rates at very high speeds (between 51- 55 Mbps) at very short distances (up to 1000 feet in length).
- Supports up to 51 Mbps at very short distances. VDSL is the high-end member of the DSL family.
x2/DSL - x2/DSL is a planned modem that will support 56 Kbps modem communication. It is upgradeable, through new software installation, to ADSL when it becomes available in the user's area.
DSL Facts
DSL is affected by distance. The greater the distance between your installation and the telephone company's Central Office (CO), the lower your speeds will be. In other words, if your home or small business is close enough to the telephone company's central office that offers DSL service, you can receive downstream data rates at up to 1.5 Mbps. That means you can download files very fast, much faster than you probably are now achieving with an ordinary 56K modem. Picture it as a continuous, uninterrupted transmission of motion video, audio, voice, and even multimedia 3-D effects. If you want to upload, your speed will be a little less (speeds can range from 640Kbps to 1Mbps), but still will be remarkably faster than when using a 56K modem.
A DSL line carries both data and voice signals on the same line. And the data part of the line is always connected. So, you can speak on the phone and use the Internet at the same time. Sometimes, a splitter is required.
It's predicted that DSL will replace Integrated Services Digital Network (ISDN) in many areas in the near future. It will also replace or be a better option than the cable modem currently available for bringing multimedia and 3-D effects to homes and small businesses.
Application
Dedicated, high speed Internet access enables many applications. These include the capability to host email, web sites, web-based applications at your physical business location. Applications such as these require a dedicated connection with static IP addresses. Furthermore, applications such as ICQ or AOL chat can always be on. These applications can add to you and your staff’s productivity.
One of the flavors of Internet access is DSL. One of the chief productivity benefits is the ability to rapidly transfer and download files, conduct video conferencing and play streaming multi-media from remote Web Servers. This applies to both home and business settings. Below is a matrix of the average time it takes for file sizes to transfer depending on the circuit speed.
Results for 256k transmission speed: |
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Results for 1544k transmission speed: |
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The Theory column represents the fastest possible time given file size and transmission speed.
The Reality column represents the most likely time given the network overhead, congestion and shared use. For presentation purposes, time is doubled.
Installing DSL
Here's some basic guidelines provided by the telephone company for installing DSL at your home or business:
- Central Office Availability. For you to use DSL, it must be available from your telephone company central office (CO) or a neighboring facility Incumbent Local Exchange Carrier or Competitive Local Exchange Carrier (these are sometimes called ILECs or CLECs).
- DSL Availability. DSL cannot travel more than a distance of approximately three miles. If your office is more than three miles away from your telephone company's central office, we may not be able to provide DSL to you.
- New Wiring. In most cases, DSL can travel over the traditional copper wires already installed at your home or business. In some cases, DSL may require a different jack and, occasionally, new wiring. The telephone company can complete the wiring for you, you can do it yourself, or you can hire an independent contractor.
- Splitter. Depending upon the type of DSL you want, or the type of DSL available in your area, a splitter may be required to be installed.
- DSL Modem (DSL LAN) and an Ethernet Card. A DSL Modem and an Ethernet card are required for DSL installation. The modem will be provided by your service provider. If your computer does not already have an Ethernet card, the service provider will install one externally.
- Compatible Long Distance Carriers and ISPs. If you want to make long distance voice and Data calls using DSL, you must choose a Long Distance Carrier with lines capable of transmitting data at DSL's top speed of 8Mbps. If you want to use DSL to download data (down streaming) or transmit data over the Internet (up streaming), your Online or Internet Service Provider must have a DSL interface capable of taking full advantage of DSL's capacity. This may mean extra charges for you, so contact your provider.
- Back-up Power Supply. Unlike your analog telephone line, your DSL line does not draw its current from your telephone carrier central office and needs a separate power supply should your power go out. An Uninterruptable Power Supply (like the ones used with your PC's) can be used to maintain DSL communications during a power failure. DSL uses regular (120v) current.
Requirements for your PC/Mac and DSL
In order for you to take full advantage of DSL's many features, your home or business's technology must be current enough so that it is compatible with the DSL equipment on the market. Make sure that your equipment is compliant with the requirements in the following paragraphs.
A prerequisite for installation is that your computer must have a Peripheral Component Interconnect (PCI) slot for installing a PCI. PCI adaptor cards may also be necessary. Your local telephone company may need to install these cards that insert into the PCI slot. These cards combine the Ethernet interface to your PC with DSL modem functions.
For single-user home based customers, a Universal Serial Bus (USB) modem is generally required. Most new PCs are equipped with USB ports that support the USB modems. For businesses with multiple users, a hub with Ethernet cabling, or a router, is generally required.
Most DSL terminal equipment is optimized to interface with the following:
- 486 PC with Windows 95, 98, or NT Workstation.
- Pentium PC with Windows 95/NT.
- Apple Macintosh Plus with MacOS 7.x.
Each piece of DSL terminal equipment will have its own individual requirements. Call your service provider if you're not sure whether your computer meets the basic requirements for DSL.
DSL FAQs
What is DSL?
How is DSL different from analog transmission?
How does DSL work?
Does DSL work with my existing phone wires and equipment?
Can I install DSL?
Will I experience noise and interference on the phone lines?
What are the most popular and widely deployed flavors of DSL?
What is Asymmetric DSL (ADSL)?
What is Symmetric DSL (SDSL)?
What is DSL-Lite (also called G-Lite)?
Do I need to dial-up when using DSL?
What are some of the uses of DSL?
Can I talk on the phone and use another device, such as PC or fax, at the same time?
What are some features of DSL?
What are some of the benefits of using DSL?
How much does DSL cost?
What if I want to know more?
Q: What is DSL?
Digital Subscriber Line (DSL) is a new digital technology that brings high-bandwidth to homes and small to medium sized businesses (SMBs) over the ordinary copper telephone lines presently installed behind your walls. DSL technology is available in various flavors, collectively referred to as xDSL. It allows voice, video and data to be transmitted at very fast speeds, 20 or more times faster than an ordinary 56K modem and 10 times faster than ISDN.
Q: How is DSL different from analog transmission?
Analog transmission only uses a small portion of the available amount of information that can be transmitted over copper wires. As a result, the maximum amount of data that you can receive using an ordinary modem is only about 56 Kbps, a fraction of what is possible when using DSL.
DSL is a digital service. It brings voice, video and data on the same line digitally. DSL uses more bandwidth than analog to bring large amounts of information to your lines.
Q: How does DSL work?
DSL brings voice, video and data over the ordinary twisted pair copper wires currently installed at your business. It uses only one path for carrying voice, video and data. It uses a high bandwidth to increase capacity for transmissions.
Q: Does DSL work with my existing phone wires and equipment?
Yes, but it may require special jacks and connections, or changes to your inside wiring. Your service provider may need to install new wire depending on the type of DSL flavor you choose for your business. A splitter is usually required, depending on the flavor of DSL you want, or the type of DSL available in your area. G-Lite DSL does not require a splitter.
A DSL modem and an Ethernet card are also required for installation. Your service provider usually installs these components. However, you may be able to install these components yourself. Check with your service provider.
Q: Can I install DSL?
There are many flavors of DSL available for your business. The flavor you select will depend upon your business needs. Installation requirements will vary according to the flavor you choose for your business. For some DSL flavors, you may be able to do the actual installation yourself. Check with your service provider.
Q: Will I experience noise and interference on the phone lines?
No. The digital quality ensures that your transmissions arrive crystal clear, free of the "noise" associated with phone lines. Both noise and interference are minimized with this new digital technology.
Q: What are the most popular and widely deployed flavors of DSL?
The most popular and widely deployed flavors of DSL include the following:
- ADSL (Asymmetric Digital Subscriber Line): A version of DSL that delivers up to 8 Mbps downstream (i.e., downloading) and 640 Kbps upstream (i.e., uploading). It is used mostly for down streaming where files can be downloaded very quickly from Internet server to client.
- SDSL (Symmetric Digital Subscriber Line): A version of DSL used to transmit voice and data in both directions simultaneously.
- DSL-Lite (also called G-Lite): A version of ADSL that delivers up to 1.5 Mbps downstream and 384 Kbps upstream.
Q: What is Asymmetric DSL (ADSL)?
Asymmetric DSL has a downstream speed greater than an upstream speed. This type of transmission model reflects the Internet client/server model. Down streaming is a flow of data from the Internet server to a client, and up streaming is a flow of data from your business premises to the Internet.
Q: What is Symmetric DSL (SDSL)?
Symmetric DSL provides a transmission flow in which both downstream and upstream directions have the same speed.
Q: What is DSL-Lite (also called G-Lite)?
G-Lite is a version of ADSL that does not require a splitter. Its downstream speed is somewhat lower than ADSL.
Q: Do I need to dial-up when using DSL?
No. DSL does not require a dial-up. DSL is an "always on" digital service. To connect, you never have to dial-up. Once your business has installed DSL, your service is "always on" and you're always connected.
Q: What are some of the uses of DSL?
DSL is used for carrying voice, data and video at fast rates. Users can download and upload large files quickly. It is also used for fast Internet access, interactive multimedia, on-line banking, shopping and stock trading, videoconferencing, and remote office or remote LAN to LAN applications.
Q: Can I talk on the phone and use another device, such as PC or fax, at the same time?
Yes. You can use two devices at the same time. This service enables you to accomplish many things simultaneously. If you currently juggle fax and voice, or fax and data communications, on a single line, or use the Internet often for business, you're a candidate for DSL.
Q: What are some features of DSL?
Fast Internet access, high bandwidth and speed, reliability, "always on" service and increased security make it highly desirable for many SMBs.
Q: What are some of the benefits of using DSL?
DSL is a cost effective solution for many small to medium sized businesses and has many benefits including the following:
- It has a variety of flavors. You can select the DSL flavor that is best for your business.
- You can use the Internet and voice/fax devices over a single telephone line.
- Your Internet access is uninterrupted and "always on".
- Web pages seem to pop up almost immediately. Files download very quickly.
- Data security exceeds cable.
- You can use it for a wide range of data services, including remote LAN access and LAN to LAN connectivity.
Q: How much does DSL cost?
DSL is a very affordable and cost-effective service based upon a flat rate. Prices vary depending upon the flavor you choose. Since cost is not based upon usage, you can use this service any time for as long as you want without incurring any usage charges. It is easily and inexpensively installed.
When selecting DSL, you should determine which flavor of DSL is best for your business. This decision will affect the price of the DSL installation and service. ADSL and G-Lite DSL are very affordable. For those businesses that need the high-end flavors of DSL with very large bandwidth and ultra fast speeds, techniques are currently being developed that will lower costs.
Q: What if I want to know more?
Just e-mail us at info@broadbandunion.com. We'll be happy to answer any questions you have about this revolutionary new way to communicate with your customers!
