GL-10
Issue 9 October 1998
363-206-204
GLOSSARY
I
ID
Identifier. See shelf ID and site ID.
IEC
International Electrotechnology Commission.
IMF
Infant Mortality Factor.
INC
Incoming Status.
INCM
A parallel telemetry point used to indicate incoming low-speed failures.
I/O
Input/Output.
IR
Intermediate Reach.
IS
In Service — One possible state of a DS1, DS3, or EC-1 port. Other possible
states are "auto" (automatic) and "nmon" (not monitored).
ISDN
Integrated Services Digital Network.
IS-3
A proprietary interface provided by the 21D optical line interface units. Used for
OC-3/OC-12 intershelf interworking.
ISO
International Standards Organization. A standards organization that creates,
writes compiles and distributes standards for mant systems and interfaces that
must be used in international technology and business communities. See OSI.
ITU
International Telecommunications Union. An international advisory committee
under United Nations’ sponsorship that has composed and recommended for
adoption worldwide standards for international communications. The ITU consists
of the ITU-R (radio, that is, free space) and the ITU-T (telecommunications,
meaning any mode that uses a medium other than radio. Fiber optics and coaxial
cable are examples of transmission technology falling under ITU-T.) The
International Telecommunications Union replaced the CCITT. See CCITT.