Microsoft Knowledge Base

• 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