ISDN

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

ISDN

Integrated Services Digital Network (ISDN) offers a much faster communication speed than an analog telephone line. The analog telephone line can communicate at speeds up to 56 kilobits per second (Kbps), whereas ISDN communicates at speeds of 64 or 128 Kbps. Businesses that need this kind of speed usually have a large telecommuting workforce or need to do extensive administrative tasks remotely, such as install software on off-site workstations.

Installing an ISDN adapter

A primary rate interface (PRI) ISDN line comes with two B channels and one D channel. Each B channel transmits data at 64 Kbps. The D channel is for signaling and transmits data at 16 Kbps.

You need to install ISDN adapters on the server and on each client. Then you can configure each B channel to act as a port, or you can configure all B channels to act as a single port. For instructions on installing an ISDN adapter, see the adapter's documentation. If you cannot configure all of the B channels on your ISDN adapter to act as a single port, then use Multilink to aggregate the multiple B channels into a single logical port.

If your business has a large number of people calling in to the remote access server, you can configure each channel to operate as a separate port. This configuration allows the greatest number of people to call in.

However, if your business has few people calling in, but needs more data-transmission speed, you can configure both channels to act as a single port. With this configuration, line speed increases to 128 Kbps. If you have installed more than one adapter, you can combine the channels on each adapter and get even faster transmission speed.

For information about installing an ISDN adapter, see To install an Install an ISDN adapter.