Microsoft KB Archive/174242

= Microsoft Knowledge Base =

Frequently Asked Integrated Services Digital Network Questions
Last reviewed: September 24, 1997

Article ID: Q174242

The information in this article applies to:


 * The Microsoft Network, versions 1.3, 2.0, 2.5

SUMMARY
This article lists frequently asked questions about using Integrated Services Digital Network (ISDN) with MSN, the Microsoft Network.

MORE INFORMATION
1. Q. What is ISDN?

A. Integrated Services Digital Network (ISDN) is a high-speed, fully digital telephone service that provides Internet access with data throughput up to 128 kilobits per second (Kbps). ISDN provides the following benefits:

- Speed: ISDN transmits information over four times faster than analog modems. That means graphics, audio, and video files on the Internet can be received much faster, and download time is        substantially decreased. If you are dialing into a corporate local area network (LAN), ISDN allows programs to run at speeds much closer to the speed of the LAN in the office.

- Clear connections: ISDN transmits data digitally and, as a        result, is less susceptible to noise than analog transmissions. Data connections are virtually error-free. Analog modem connections must dedicate some bandwidth to error correction and retransmission. This overhead reduces the actual throughput, while an ISDN line can dedicate all its bandwidth to data transmission.

- Rapid call setup: In addition to raw speed, ISDN calls can be set up much faster than analog phone calls. While an analog modem can take up to a minute to set up a connection, you can be        transmitting data in about two seconds with ISDN. Because ISDN is fully digital, the lengthy handshaking process of analog modems is not required.

2. Q. Does ISDN require a special cable?

A. No. ISDN uses the same cable as your existing telephone system. Most lines do not require any special conditioning to provide ISDN service because the existing telephone system is digital. Typically, the only analog connection is from the telephone company to your home or office.

3. Q. What do I need to use ISDN with MSN?

A. Unlike analog telephone service, ISDN service is not yet available everywhere. Your telephone company must have the necessary equipment installed in the central office that serves you. You must also have an ISDN adapter.

4. Q. How do you know if your telephone company has the necessary equipment?

A. Contact your local telephone company to find out if they have ISDN equipment, or you may find the information at the following Microsoft Web site:

http://www.microsoft.com/windows/getisdn/default.htm

5. Q. How are ISDN networks configured?

A. The most common Basic Rate Interface (BRI) ISDN divides the telephone line into three digital channels: One delta (D) channel for signaling, and two bearer (B) channels for data, each of which can be used simultaneously.

ISDN may also use a Primary Rate Interface (PRI). These networks use either 24 (23 B plus one D) or 31 (30 B plus one D) channel interfaces. These types of configurations are usually found in     corporate PBX, telephone company, or long distance carrier offices.

ISDN uses a terminal adapter, which replaces the modem, to adapt the channels to existing equipment. Traditional telecommunications equipment, such as telephones and fax machines, can also be attached to the BRI if they have the proper hardware and software interfaces.

6. Q. What is the difference between single-channel and dual-channel ISDN?

A. The following descriptions of single-channel and dual-channel ISDN are based on BRI:

- Single-channel ISDN uses one B channel, which means you can connect at 64 Kbps or 56 Kbps, depending on your carrier.

- Dual-channel ISDN combines both B channels of your ISDN line using Multilink PPP (MP) to connect to the Internet up to 128 Kbps. If you make a dual-channel call, you cannot use your second channel for other applications, such as fax or voice calls.

Currently, all of the MSN ISDN telephone numbers in the United States and Canada can receive dual-channel calls. Dual-channel ISDN is not supported outside of these two countries. MSN is     investigating offering dual-channel ISDN services in other international markets.

7. Q. How is BRI set up?

A. ISDN service connects your home or office to the telephone company through a U interface. The U interface, which can be no more than 18,000 feet in length, is a two-wire connection that connects the wall jack in your home or office to the telephone company central office. At the central office, the U interface connects to a Network Termination (NT-1) device. The NT-1 device is often built into ISDN hardware. The NT-1 device terminates the U interface and converts it     to a T interface for use by terminal adapters.

8. Q. What is a SPID?

A. A Service Profile ID (SPID) is used to identify which services and features are supplied to the ISDN connection. SPIDs usually consist of the ten-digit phone number, plus a prefix and a suffix to     identify additional services. If a device is configured without a     SPID or with an incorrect SPID, it is unable to establish and maintain a network connection, even though the basic transport mechanism has been established.

9. Q. How do I obtain ISDN service?

A. To learn about ISDN, download free ISDN software, and electronically order an ISDN line from participating telephone companies in the United States, Canada, or other countries, visit the following Microsoft Web page:

http://www.microsoft.com/windows/getisdn/default.htm

10. Q. How can I sign up for MSN using ISDN?

A. If you are not an MSN member, you need to use an analog modem to      set up MSN and to open an MSN account. For information about how to      install MSN, please see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q174200 TITLE    : How to Install The Microsoft Network Version 2.5

If you are an MSN member, use your MSN account. To connect using ISDN, use the following steps:

1. Click Start, and then click The Microsoft Network.

2. On the MSN Sign-In screen, click Settings.

3. Next to the Phone Number box, click Phone Book.

4. In the Service Type box, click ISDN.

5. Click the appropriate entries in the Country, State Or Region, and Access Numbers boxes, and then click OK.

6. Repeat steps 3-5, but click Phone Book next to the Backup Number box in step 3.

11. Q. What is the MSN plan for ISDN?

A. MSN is dedicated to providing the highest-quality package for Internet users and delivering the best content available on the Internet. Currently, MSN offers one of the largest ISDN Internet networks, with 724 local access locations worldwide. More than 325 U.S. locations support the point-to-point protocol (PPP) and multilink PPP (MP). PPP and MP allow throughput rates up to 128 Kbps.

12. Q. How much does ISDN phone service typically cost?

A. ISDN phone service rates vary with each telephone company. The rate usually includes a basic ISDN service, and additional per-minute charges. There may also be an initial setup or installation fee. Contact your local telephone company to find out what ISDN costs in your area.

13. Q. Which ISDN adapters are supported by MSN?

A. For information about the ISDN adapters supported by MSN, please see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q174019 TITLE    : Integrated Service Digital Network Adapters Supported by MSN