Integrated Services Digital Network (ISDN) adalah satu set dari standar CCITT/ITU untuk transmisi digital melewati kabel telepon seperti halnya media lainnya. ISDN adapter dapat mengambil gambar besar dengan kecepatan tinggi (lebih dari 128 kbps). Untuk memasang ISDN ini dibutuhkan adapter di kedua sisi pengguna dan ISP. (www.whatis.com)
ISDN terbagi menjadi dial-up ISDN dan dedicated ISDN,
is a set of CCITT/ITU
standards for digital transmission over ordinary telephone copper wire as well
as over other media. Home and business users who install an ISDN adapter
(in place of a modem)
can see highly-graphic Web pages arriving very quickly (up to 128 Kbps).
ISDN requires adapters at both ends of the transmission so your access provider
also needs an ISDN adapter. ISDN is generally available from your phone company
in most urban areas in the United States and Europe.
There
are two levels of service: the Basic Rate Interface (BRI),
intended for the home and small enterprise, and the Primary Rate Interface (PRI),
for larger users. Both rates include a number of B-channels and a D-channels.
Each B-channel
carries data, voice, and other services. Each D-channel
carries control and signaling information.
The
Basic Rate Interface consists of two 64 Kbps B-channels and one 16 Kbps D-
channel. Thus, a Basic Rate user can have up to 128 Kbps service. The Primary
Rate consists of 23 B-channels and one 64 Kpbs D-channel in the United States or
30 B-channels and 1 D-channel in Europe.
Integrated
Services Digital Network in concept is the integration of both analog or voice
data together with digital data over the same network. Although the ISDN you can
install is integrating these on a medium designed for analog transmission, broadband
ISDN (BISDN)
will extend the integration of both services throughout the rest of the
end-to-end path using fiber optic and radio media. Broadband ISDN will encompass
frame
relay service for high-speed data that can be sent in large
bursts, the Fiber Distributed-Data Interface (FDDI),
and the Synchronous Opical Network (SONET).
BISDN will support transmission from 2 Mbps up to much higher, but as yet
unspecified, rates.