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Business High Speed

Frequently Asked Questions

DSL Questions:

What is DSL?

DSL (digital subscriber line) technology delivers high-speed Internet access through standard telephone lines. Because it combines high availability and reliability at affordable rates, DSL can give businesses a cost-effective solution for broadband connectivity. The right DSL service can support various essential business functions, including access to the Internet and corporate wide area networks, enterprise applications, transaction processing, large file transfers, and voice and video.

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Do I need to have telephone service to run DSL?

DSL does require a phone line. This line can run both voice and DSL service at the same time (a shared line) or DSL service only (a dedicated line).

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What is the difference between SDSL and ADSL?

With symmetrical DSL (SDSL), download and upload speeds are equal. With asymmetrical DSL (ADSL), download speeds are higher than upload speeds. Businesses with significant uploading activity--including large file transfers or emails, web hosting and document conferencing-are best served by an SDSL solution. SDSL also has the advantage of being a dedicated-line service and is supported by uptime and service-level guarantees.

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What is the difference between a shared line and dedicated line?

Dedicated-line DSL service more consistently delivers its available bandwidth. Shared-line services are a more economical option compared to dedicated-line services, but their connection speed is more likely to vary. This inconsistency is the reason why shared-line DSL products may show a range of available speeds (e.g., "up to 3.0M") and carry a lower service level guarantee ("best effort"). Shared-line DSL services also come only as ADSL technology.

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What kind of equipment do I need in order to use EarthLink Business Solutions DSL service?

You will need a router and, if you are using a shared-line product, DSL filters (small boxes that filter out the DSL signal). EarthLink Business Solutions will provide all the equipment that you will need. There is no cost to you after rebate.

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How do you determine whether my business qualifies for DSL service?

DSL service is "distance-sensitive," which means that performance may be affected by your location's proximity to the nearest central office of telephone switching equipment. The distance must be within a certain limit or you may not be able to receive DSL service. We can determine your DSL qualification through two different resources. The first resource is the prequalification form on the right-hand side of this page-just fill in your information and click the "Check Availability" button. The second resource is our sales line-when you call 1-866-576-8441, our salespeople will ask you a few questions to determine if we can provide DSL service at your location. If you would like to know more, see our "Prequalification Questions" section in this FAQ.

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T1 Questions:

What is a T1?

T1 Internet access service offers a high level of bandwidth and reliability. EarthLink Business T1 provides bandwidth in your choice of three increments (1.5Mbps, 768Kbps, 384Kbps) with symmetrical upload and download speeds. EarthLink also offers Enterprise T1/T3 service for even higher available levels of bandwidth. There are no distance limitations affecting the availability of T1 service, and both uptime and bandwidth are guaranteed by rigorous service level agreements. Although T1 service is more costly than DSL, it is an ideal solution for businesses with high broadband and network demands.

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What are the main technology differences between T1 and DSL service?

For the purpose of explanation, a full T1 line will be compared to a 1.5Mbps SDSL connection.

  • 1 Dedicated Pair vs. 2 Dedicated Pair: SDSL utilizes one insulated twisted pair for its services that it does not share with the telephone line. T1 services utilize 2 pairs of twisted pair. One pair is used for receiving data while the other is used to transmit the data.
  • Oversubscription: One of the primary differences between DSL and a T1 is in the level of oversubscription. The T1 products offer a customer a truly dedicated circuit that does not get multiplexed with other circuits on its path to a PoP and then onto the Internet. DSL technologies offer dedicated circuits to the central office of telephone switching equipment; however, at the C.O. DSL circuits enter the DSLAM (Digital Subscriber Line Access Multiplexer), which funnels (or multiplexes) several circuits onto a single circuit. This action is called oversubscription.
  • T1 can be delivered over fiber as well as copper (4-wire) while SDSL can only be delivered across copper (2-wire).
  • Distance: T1 services are not limited by distance and are engineered to extend tens of miles. T1 services are widely available in the United States. Loop lengths and distance qualifications are usually not a concern. DSL is distance-dependent.

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What equipment is needed for EarthLink Business T1 service?

EarthLink T1/T3 customers must have routers with a CSU/DSU (channel service unit/data service unit) to connect to EarthLink's service.

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Does EarthLink provide routers and CSU/DSUs?

Yes. Typical routers that are sold with EarthLink T1 service include the Cisco and Netopia brand routers. The Netopia routers come with an internal CSU/DSU. Cisco routers can be sold with both internal and external CSU/DSUs. This equipment is free after rebate.

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How does EarthLink Enterprise T1/T3 service compare to other dedicated access types?

EarthLink T1/T3 service is the highest-level business-class product available. It is designed to meet the needs of business customers by including features such as static IP addresses, DNS services, router configuration and management, a Service Level Agreement, and a dedicated account manager and installation coordinator. In the event of a service outage, EarthLink T1 and T3 services are treated as the highest priority service with respect to mean time to repair (MMTR). EarthLink targets a maximum of 4 hours to repair your service. EarthLink T1 and T3 products are also guaranteed to provide 99.99% uptime, 100% network availability, average packet loss of less than 0.01% and Latency of less than 65ms. Please reference your SLA for details.

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How reliable is a T1?

Our T1s come with an uptime guarantee of 99.99%.

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What is the general expectation during a T1 installation?

T1 lines/circuits are commonly provisioned using two dedicated specially conditioned unshielded twisted pairs with repeaters positioned every 6,000 feet. A Local Exchange Carrier (local telephone company) for your location provisions this circuit between your premise and EarthLink's POP (Point of Presence). This requires a provisioning period of between 30 to 45 days. EarthLink's Installation Coordinator will work with you and the Local Exchange Carrier to ensure the provisioning of your T1 circuits happens smoothly and as quickly as possible.

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Product Availability Questions:

Why does your prequalification form ask for my address and phone numbers?

Our prequalification tool uses your address and phone number to calculate your business location's geographic distance from the nearest central office of telephone switching equipment.

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What is the difference between "Service Phone" and "Contact Phone"?

The contact phone number is the telephone number where you can be reached. The service phone number is the number where you would like Internet access.

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What if I do not know my "Service Phone" number?

If you do not know your service telephone number, you have two options:

  • Enter the phone number of a residence or business geographically close to your location.
  • Call our sales line at 1-866-576-8441. Our salespeople have tools for determining service availability that are not available online.

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If your prequalification tool tells me there is no service available in my area, can you still help me?

Yes. From time to time our prequalification tool does not yield correct results. In this case the best course of action is calling our sales line at 1-866-576-8441. Our salespeople can determine service availability using their specialized applications.

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Other Questions:

What's the difference between EarthLink Business Solutions and EarthLink?

Yes. EarthLink Business Solutions the business division of EarthLink. When you call our sales lines you will be connected to our sales people in Vancouver, Washington. Corporate Headquarters is located in Atlanta.

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Does EarthLink offer Web Hosting?

Yes. EarthLink Web Hosting is located at

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Where can I get more information or support for EarthLink's residential services?

Please call 1-888-829-8466 or go to

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