Sprint ISDN FAQ

FAQs

What kind of equipment do I need for Sprint's ISDN service?
Depending on the intended use and the configuration of computers and phone equipment at a particular site, there are several pieces of equipment needed to install ISDN.

Terminal Adapter — A terminal adapter (TA) is the ISDN equivalent of an analog modem. People often refer to TAs as ISDN modems, but that term isn't technically correct. Modems modulate and demodulate signals, and there's no modulation and demodulation necessary with the digital transmission used by ISDN. TAs let the computer talk to the ISDN circuit, control the calls, and manipulate the B channels for effective communication.
Network Terminator — Connecting ISDN to a personal computer requires a network terminator (NT1) and ISDN terminal adapter. The NT1 plugs into the two-wire line from the telephone company with an RJ-11 connector and provides output to the TA. Within the U.S., the NT1 is typically built into the TA, but in Europe and Japan, they are separate devices.
ISDN Router — An ISDN router is a device that enables several users on a network to access the Internet via ISDN. Also known as an ISDN LAN modem, it contains a BRI ISDN port and an Ethernet port. It may also provide several Ethernet ports, which lets it serve as a central Ethernet hub for a small workgroup. Access to the unit for configuration and monitoring is typically done via a Web browser.

For Internet access, the ISDN router supplies temporary IP addresses to each of the nodes through its DHCP capability. Routers may also provide analog phone support.

Do I need special wiring for ISDN?
Fortunately, most current telephone wiring works with ISDN, so you will need only a plain phone jack, known as a U interface.

Can I continue using existing analog telephones and equipment?
Yes. A special terminal adapter supporting analog to digital conversion is necessary to use analog phone equipment with an ISDN line and is available from a number of different vendors. Although ISDN service supports using it, analog telephone equipment limits the added functionality that Sprint ISDN connectivity provides.

Which is better, ISDN or ADSL?
Assuming both ISDN and ADSL are available in your area, the choice depends on a number of factors:

If you frequently use two or more telephone lines for voice connections, ISDN may be attractive to you. This is especially true if you typically connect to the Internet several times a day but for only an hour or two. An ISDN BRI line supports not only 128 kbps Internet access but also two telephone connections (voice) and a fax connection.
If a high-speed and/or a dedicated, 24 x 7 Internet connection is what you are looking for, then ADSL is probably the right solution.
If you need the option of high-speed direct-connect to remote networks other than the Internet, e.g., to a company intranet or for videoconferencing, then ISDN is a good choice.