DSL: Terminology and Definitions

DSL Technology Distance from the CO - Central Office is key. Not in physical feet but circuit feet.

What is DSL?
DSL stands for Digital Subscriber Line. DSL is a technology that uses a standard copper two-wire pair (or line) to transmit high speed (high frequency) Internet connectivity to areas that will support the service.

How fast is DSL?
DSL can obtain speeds as high as 1.5Mbps and above, but the speed your location can receive depends on your address, line quality and the distance to your local phone company's central office (CO). A Central Office is the main switching station for the phone lines in your area. It is the office where the ILEC (your local telephone company) connects the phone circuits, and makes the routes between local and long distance. The signal degrades ( gets slower ) the further away you are, normally about 15,000'. IDSL may reach up to 18,000' and only reaches speeds between 144k - 128 kps.

Can I get DSL in my area? DSL service can only be delivered within a radius from your phone company's local central office. Distance from the CO - Central Office is key. Not in physical feet but circuit feet. Typically, your highest speed service is restricted to a distance of 15,000 feet from the central office it is served from. An example: Depending upon how your community grew, often DSL connections can run 6 blocks east then 10 blocks west before running north or south again. This adds the the total distance of the circuit. This is critical. Costs go up and available services go down the further away you are from the CO. Residential  DSL Service  Business Class  DSL

What are the "types" available?
There are several kinds of DSL services. The speeds and type of DSL available to you depends on two factors primarily: 1) Your distance from the phone company's Central Office (CO) and 2) the type of lines used between you and the Central Office (fiber/copper). Each type of DSL has a different price, and different important attributes.

ADSL - Asymmetric DSL is available up to 15,000 feet from a CO. Typically the download speed is faster than the upload speed. The circuit  connection transmits information over the copper wires that make up the local loop of the public switched telephone network.  It bypasses the circuit-switched lines that make up that network and yields much faster data transmission rates than analog modem technologies.  ADSL service is also referred to as RADSL (Rate-Adaptive ADSL).

The term "rate-adaptive" means the technology adapts to your individual line conditions, e.g., your specific distance from the CO and the quality of the copper line that serves your DSL. Speeds expressed with ADSL packages are the maximum speeds your line may achieve. Although we will do everything within our power to provide you with the best possible service, due to the nature of the technology, ADSL services do not come with a service level guarantee. The actual speed is determined by both distance & copper quality, and installations resulting in "best business effort" speed (the maximum achievable speed based on technical conditions prior to install) will be considered successful. As many businesses require a guaranteed service, We recommend SDSL service for all eligible businesses.

SDSL - Symmetric DSL, able to be served up to 8,000 +/- feet from a CO. SDSL services deliver the same rate of download speed as upload speeds. It is a more robust connection, which is guaranteed at a certain level of connection speed. Often referred to as "naked dsl". Unlike ADSL, SDSL does not require you to have an existing phone line with your local telephone company or subscribe to analog telephone service. Since the service is "symmetrical", you can expect upload speeds to be equivalent to download speeds in most instances. Normally, you will need a more expensive and reliable SDSL or T1 connection if you plan on hosting your own web or mail servers.

IDSL - IDSL is based on ISDN, an older technology that was designed to work well with existing ISDN transmission methods. SDSL, and ADSL travel over regular copper lines and cannot have any electronics on them (such as, for example, amplifiers or repeaters - commonly used to "boost" the voice signal on conventional telephone lines). Some ADSL, and SDSL orders cannot be fulfilled because of electronics or distance issues that are uncovered during the ordering process. In that case, IDSL may be the best solution. IDSL has the ability to work over great distances, and through certain types of electronics. If you are very far away from a Central Office, or there are electronics on the copper line you are given by your phone company, you may still be able to get broadband service using IDSL.

T1 - T3
T1 service is a high-speed data (and voice) protocol that has been the preferred industry standard method of broadband connectivity for close to three decades. Utilizing both four wire copper lines and more advanced fiber-optic lines. T1 standard of 384 kps, 512, 768 and 1.5Mbps at far greater distances and higher speeds than standard DSL services. T1 is DSL on steroids. Since DSL is data based, a T1 Data line has been discussed here. Voice, data or integrated (both) is an option. T1 Terms defined. To check availability and instant pricing of T1 or DS3 at your location visit or quote page: T1 rate quote

Broadband via Satellite
Broadband via satellite is a wireless technology that requires no connection to your local telephone or cable company. Unlike DSL and cable modem technology, satellite broadband service is available anywhere in the U.S. with a clear view of the Southern sky.  All systems include professional installation with your subscription. A local installer will make certain that your location is not obstructed by trees or other objects prior to performing the actual installation. While broadband via satellite may be a good choice for small, rural businesses with no other means of connectivity, it is not generally recommended for tasks other than web surfing, uploading/downloading files and sending/receiving e-mails. This type of connection is not suitable to industries that must protect client sensitive information like Banks, Legal and Medical services. Non PCI Compliant broadband service. Specifically, satellite broadband can not be used for VPNs or for most server-type applications. These include VoIP, video conferencing, streaming audio and video, interactive simulations or video games, or if your business accepts cashless payments etc. We do not recommend broadband via satellite for these applications.

Fixed Wireless Broadband
Requires "line of sight".  If your located in a gully or blocked by a hill or even another large office building you may not be able to connect to a tower. Also, if your business accepts cashless payments, you're most likely aware of the payment card industry‚Äôs efforts to reduce credit card fraud and identity theft. Some providers meet PCI Compliant broadband service requirements and offers both private Layer 2 connectivity or a Private/Public option. Accel networks meets PCI standards.

How is DSL delivered to my business? Business customers are provided with a DSL service that runs over a second, unused pair of copper wires running into your location or 3G wireless. Your phone services and DSL service are on completely different wiring.

Check for Business DSL Service. Our List of preferred Business Class DSL Providers.

Ordering DSL

Do I need to have phone service through a specific phone company to order service?
Customers ordering DSL must have voice service on the service number provided through one of the ILEC's in their area. ILEC stands for Incumbent Local Exchange Carrier. Some examples are:

  • CenturyLink
  • Pac Bell
  • Verizon (both East and West Coast branches)
  • Southwestern Bell
  • Ameritech
  • SNET
  • Bell South
  • Sprint

Can I specify a preferred line vendor?
An excellent DSL provider places your order with a line vendor of our choosing. The decision of which vendor you are placed with typically is made based on availability of that vendor's service at your location, price, and speed to installation record.

DSL Installation

How long will it take to get DSL installed?
Depending on location and line availability issues, it can take anywhere from 12 to 45 business days on West Coast as well as through ILECs (local telephone companies) such as Ameritech. On the East Coast, installation is usually around 20 to 45 business days.

Who is involved with installing my DSL?
There are three companies you should be aware of in this process:

  1. The ILEC: (Incumbent Local Exchange Carrier, also known as the phone company) Every provider of phone-provided internet connectivity has to interact on some level with the ILEC as they essentially "own" the physical wiring infrastructure from the Central Office to your home. This includes all the wiring, phone poles, and phone boxes. They are responsible for installing any physical connections.
  2. The CLEC: (Competitive Local Exchange Carrier) The CLEC leases the basic infrastructure from the ILEC to provide a separate, private, ATM layer of the Internet connection. We use connections through a CLEC because of the more robust and customer friendly data networks and speedy delivery.
  3. The ISP: The third layer of this service. The third layer of the internet connection is the service and IP layer. An excellent provider connects you to the services that give your DSL connection value, such as email, web-hosting, static IP addresses, as well as provide complete customer support and billing functions.

Another computer analogy that might make this easier to understand is to think about purchasing a computer. If you are looking for a value computer service, you purchase from a name brand company who does the following:

  1. Buys the parts from another company to build the bare bones hardware of the computer.
  2. Uses another company to purchase the OS and/or software (say Windows as the OS and various virus protection software).
  3. Finally, provides the support, delivery, billing, and added features (like warranty) themselves.

Hardware and DSL Network

Can I provide Internet access for multiple computers with a single DSL connection?
Yes, depending on the speed you get, many users can simultaneously use the same DSL connection.

How is my DSL line connected to the Internet?
Your DSL line is directly two hops from your location. It is connected to routers and Internet backbones, including MCI, Sprint, Alternet/UUNet, AT&T, Verizon which are served by DS3 and OC3 connections.

What additional computer equipment do I need to use DSL?
Each computer using the DSL for Internet access requires an Ethernet card. Using more than one computer with DSL also requires an Ethernet hub. If you wish to connect multiple computers to the DSL hardware, you will need to provide the necessary Ethernet hub and cabling for those computers. You can also setup a WiFI by using a wireless router and PCI or wireless cards in your laptops or notebooks.

Can I use a modem I already have from another DSL service?
You may use a modem from a previous DSL service providing it is supported by your new DSL provider.


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