Q. What is ISDN?

A. Integrated Services Digital Network. Qwest Single Line ISDN Service applications include Internet Access, OneStop Shopping and Telecommuting. To explore these and other applications, click here.

Q. What is Qwest Single Line ISDN Service?

A. Qwest Single Line ISDN Service is a platform-based, switched digital service offering fast, flexible, highly reliable, and digitally clear connections with the simplicity of dialing a telephone. With Qwest Single Line ISDN Service, the same pair of wires delivers one communication-at-a-time basic phone service to business or residence customers. ISDN provides two primary, high-speed (64 Kbps) communications channels that may be used simultaneously and independently to carry any combination of data, image, video or voice calls. By combining these channels, data transfer at up to 128 Kbps may be achieved. Qwest Single Line ISDN Service is available in most areas. Availability depends on your distance from the Qwest Serving Office and technical phone line qualifications. Additional equipment may be required.

Q. What is basic rate ISDN?

A. Basic rate ISDN is the name for Qwest Single Line ISDN Service. It consists of up to three distinct channels on one pair of wires: one or two B (bearer) channels, and one D (delta) channel. Basic rate ISDN is offered on either an individual case basis or in a packaged offering as Qwest Single Line ISDN Service.

Q. What if I have a local calling area and telephone number that is different from my main office?

A. If you are provided service from a designated central office which is not your normal serving office, the local calling area for your single line ISDN Service will be that of the designated ISDN equipped central office.

Calling areas are subject to change as additional central offices become capable of directly providing ISDN services to your own and nearby serving area. Changes to calling areas will affect your telephone numbers.

Q. What is a service profile identifier?

A. A service profile identifier (SPID) is your 10-digit telephone number with a suffix that contains the number one four times, and it describe a specific ISDN device to the network. As an example, a typical SPID in looks like this - 20655555551111 - 206 is the area code, 555-5555 is the telephone number and 1111 describes the ISDN device to the network.

Q. Why do I need a service profile identifier?

A. It is technically possible to attach up to eight different devices with 64 separate telephone numbers to a single ISDN telephone line. The service profile identifier is used to identify each device to both local switch and worldwide telephone networks.

Q. What is the D channel?

A. The D (delta) channel carries signaling and/or packet data information at speeds up to 16 Kbps on Single Line ISDN Service. The D channel has both data and signaling functionality, however, it does not have voice capability.

Q. What is B channel?

A. The B (bearer) channel carries circuit switched voice and/or data communications at speeds up to 64 Kbps from your premises over the loop facility to the central office.

Q. What is B channel circuit switched data?

A. Circuit switched data provides the capability of making data calls over the public switched network. Information is transmitted the same way as digitized voice. Like a voice call, a circuit-switched data call ties up network/system resources for the duration of the call. Similar to voice, calling line identification functionality is provided.

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