Technical Information

A: DSL provides simultaneous voice and high-speed data services over a single pair of copper wires. DSL technology allows data transmission at speeds much faster than the best available analog and digital modems.

A: There are several variations of the DSL products that use copper cabling to move data between the end subscriber and the host location. Data is separated from voice traffic at the serving central office and then connected to a high-speed data network and delivered to the host destination. Some forms of DSL technologies include: HDSL, SDSL, RADSL, ADSL, and VDSL. These technologies may be incorporated into the network to deliver Qwest Broadband™ as they become available and are evaluated for service delivery.

A: Different applications require a variety of speeds in order to transmit data. Therefore, DSL based services offer the appropriate amount of bandwidth to the user for his or her specific application. There are multiple line coding techniques used by the DSL vendors. Each of these techniques has strengths and weaknesses within a telephony network. Some DSL technology is intended for use in campus environments and others work well within a building. Technology for telephony must be compliant with certain standards to prevent interference and cross talk.

A: HDSL is a technology using 2B1Q line coding and offering bi-directional data transmission with both upstream and downstream traffic traveling at the same rate.

ADSL also offers bi-directional data transmission but the downstream traffic travels faster than the upstream traffic. For example, the user's upstream connection may be at 128 Kbps while the downstream connection would be at 1.5 Mbps. In certain applications, such as surfing the Internet, the user needs more bandwidth while downloading information from the Internet and therefore the ADSL technology works well.

A: While one is transmitting data over the telephone wire or local loop, line conditions on the local loops vary all the time. Rate Adaptive Digital Subscriber Line (RADSL) is able to adapt to the changing line conditions on the local loops. In fact, RADSL is able to adapt to these changing conditions as they are happening.

A: Qwest Broadband™ services do have some things in common with IDSN. However, each has a place in !NTERPRISE's portfolio of services which is designed to fully meet its customer's expectations. Customers who require ISDN's switched, multi-point capability, for applications such as videoconferencing, will find ISDN an attractive solution. Future applications of DSL will offer a multi-point solution. We have tens-of-thousands of existing ISDN users today, and some of them may decide to change to our Qwest Broadband™ offerings while others will continue to find ISDN perfectly matched to their applications.

Many customers needing the ability to access their corporate LAN or the Internet for long periods of time will find the always­on and higher­bandwidth capabilities of the DSL technologies very attractive. One of the greatest benefits of the Qwest Broadband™ offerings is that the data avoids the contention of the voice network since it is transferred over a dedicated data network.

A: The DSL technologies offer a dedicated, point­to­point connection that is always on, while ISDN requires call set­up and dial­access time in order to be activated. Also, with our Qwest Broadband™ offering based on DSL technology, there is flat­rate pricing whereas ISDN connections are usually priced at a per­minute­usage basis. Finally, the DSL­based technologies are easier to provision at the Central Office than ISDN.

A: These technologies are quite complementary. We see cable-modems and the 56 Kbps modem technology as attractive solutions for the more infrequent business and consumer Internet access users where a shared capability with others is acceptable. The DSL technologies will provide a dedicated networking solution to large and small businesses and the power-user-at-home marketplace.

A: No discussion of DSL technologies would be complete without a review of cable modems. These modems use cable TV companies' coaxial networks as the transport medium. DSL technologies use the Regional Bell Operating Companies' (RBOC) twisted wire pair network.

There are two major issues that impact the deployment and use of cable modems. The first is that only about 7% of existing coaxial distribution systems are capable of two-way traffic. The cable industry is investing heavily to upgrade their facilities to a hybrid fiber/coax based network. Most coaxial networks are designed for one-way downstream distribution only, requiring the expensive replacement of distribution nodes. The second is that all subscribers on a distribution network (from 500 to several thousand homes) share the bandwidth, which can reduce an individual's throughput to analog modem dial-up speeds.

Another cable modem topic of discussion is that unterminated cable TV jacks (no TV connected and no terminating resistor cap screwed on) act as antennas on the distribution node. Any RFI-generating (radio frequency interference) equipment near an un-terminated jack injects noise into the entire distribution network. AC motors (vacuum cleaners), computer monitors, fluorescent lights, and a host of other household items generate RFI. This is not critical for TV viewing, but can adversely affect modem throughput.

A: Yes, loop qualification is required. The process will be similar to the one for ISDN only quicker since less information is necessary in order to be qualified.

A: Unfortunately, if a location does not meet the loop qualification requirements, the subscriber cannot get Qwest Broadband™. We are working with various vendors to develop a more robust solution for customers in order to provide service to those locations where access is denied at present. In the interim, if a subscriber is interested in more information on the suite of Internet services from Qwest®, please check into Consumer Internet Services. You may also be interested in other data transport products that Qwest® offers. Please visit our World of Interactive Services page for those options.

A: The subscriber's host site or MegaCentral location is responsible for the address.

A: No. All of the registration of addresses and domain conventions must be assigned, administered and managed by the subscriber's host location.

A: Rate Adaptive Carrierless Amplitude/Phase modulation line coding.

A: Qwest Broadband™ is a bridged Layer 2 service. If L2TP is supported on the end points and can be transported across the network, then it should work.

A: An Ethernet card must be installed in the customer's computer.

A: Yes. On one end the DSL modem plugs into an RJ11 jack (a regular telephone jack) and on the other end the modem plugs into a RJ45 jack with a 10Base T interface Network Interface Card (NIC).

A: Yes. At this time the customer must be within 18,000 feet from a serving Central Office.

A: Probably. However, we need to go through the pre-qualification process to ensure that there aren't any other technical issues.

A: We intend to deliver standard voice services, with switched access anywhere you can call today.

A: The minimum configuration for a PC is a 486 with a certain amount of RAM and available hard disk space. Please visit our technical requirements section for more information.

A: While we appreciate your offer to test our products, we have already tested our services extensively in our labs located in Minneapolis, Minnesota and Denver, Colorado. Additional tests have been performed on Qwest® facilities to the residences of company employees. However, we will maintain your offer on file, and should the need for beta testing arise in the future, we will contact you.

A: Unfortunately, even when you input the first three digits of your phone number, and you get a message that Qwest Broadband™ services are available in your exchange, there still may be hurdles to obtaining service. Most of the inhibitors to receiving Qwest Broadband™ services are technical in nature. We at Qwest® are developing solutions to make access to Qwest Broadband™ services more easily attainable by all. However, the following obstacles to receiving service do exist in some areas:

A: No. Qwest Broadband™ services are provisioned for a dedicated, point­to­point connection between a host and a subscriber location. The connection is a virtual private network and does not support peer­to­peer communication.

A: Yes, but under very controlled circumstances. If the customer has a router working in conjunction with the 10 BaseT connection and can capture an IP address, then they can subnet behind the router.

Some ISPs or Corporate Hosts may assign a statically mapped or fixed IP address to the MegaSubscriber. This scenario, when used in conjunction with a router can allow a number of other users access by subnetting the IP address. We are providing a Layer Two service and if the ISP or MegaCentral location assigns the address we cannot control how the end devices use the address.

If the MegaCentral host assigns a dynamically assigned IP address and provides an always on service, the end users, if they terminate the 10 BaseT connection in a router, may be able to configure subnets after determining what the IP address is. Again, this is an issue how the host end and the subscriber ends are configured.

In most cases, the connection is a single user to a single host.

A: Yes, the voice line supported by Qwest Broadband™ service is just like any other POTS line. You can connect the voice line to any device registered with the FCC to support either voice or data transmission.

A: Qwest Broadband™ services support only one voice line on the same pair of wires carrying data to the subscriber.

A: A VPN creates the effect of a private, leased line network, but without the associated design, deployment, cost and vulnerability issues. Dedicated circuits are established between the host location, the closest Central Office and the subscriber location. Dedicated circuits are not established between various subscriber locations. Routing tables are established to route the data traffic over the high­speed DSL facilities on a priority basis in order to ensure that the level of service provided is similar to that offered by a true private network.

A: Most ISPs assign IP addresses using either RADIUS or DHCP servers. It is up to your ISP if they will allow you to connect with an IP address that has been assigned to you.

A: It depends on what you have for CPE. Standard routers, bridges or hubs with a 10BaseT interface will work fine. Qwest Broadband™ services and ISDN raw interfaces are not compatible.