Integrated Services Digital Network (ISDN)
ISDN is an international standard for voice, video,
and data transmission over digital telephone or copper lines. ISDN
comes in two different types of service levels, the Basic Rate
Interface (BRI) for individuals and smaller users and the Primary
Rate Interface (PRI) for larger, enterprise size users. Both types
of ISDN consists of 64 Kbps B channels for data and 16 Kbps D channels
for control, signaling, and supervisory information.
The Basic Rate Interface consists of two 64 Kbps
B channels and one 16 Kbps D channel, providing up to 128 Kbps
service. The Primary Rate Interface consists of 23 B channels and
one 64 Kbps D channel in the United States or 30 B channels and
one D channel in Europe.
The widespread availability of ISDN throughout Northern
America, as well as most developed areas in Asia and Europe allow
for a vast number of sites to be connected through the PEACESAT
network. Although ISDN is not readily available in most Pacific
regions covered by the PEACESAT network, all PEACESAT sites are
still able to be crossconnected through the PEACESAT Network Operations
Center (NOC) in Honolulu, which is equipped with ISDN capability.
PEACESAT Honolulu currently has 18 BRI lines and 2 PRI lines in
ISDN is primarily used to connect at 128 Kbps for
video conferencing applications. Through the use of special ISDN
Inverse Multiplexers (IMUX), connections at 384 Kbps and above
can be realized through the "bonding" of multiple ISDN
B channels into a single data stream.