International Standards Organization (ISO)
An international body that standardizes goods and services. The
ISO works in conjunction with the ITU-TS for standards that
impact communications.
I/O Input/Output.
IOP Input/Output Processor.
IP Internet protocol.
ISDN Integrated Services Digital Network.
ISLU2 Integrated Services Line Unit 2.
I Series Recommendations
ITU-TS recommendations on standards for ISDN services, ISDN
networks, user-network interfaces, and under work and
maintenance principles.
ITU-TS International Telecommunication Union — Telecommunication
Standardization Sector (formerly the CCITT).
Kbps Kilobits per second; sometimes written as Cab/s.
Layer A partition of a layered architecture that performs a defined set
of functions and presents those functions to the layer above via
a defined interface. A layer uses the functions of the set of
layers beneath it to perform its functions. The term layer is
synonymous with the term level.
LED Light Emitting Diode.
LEN Line Equipment Number.
Level See Layer.
Limited Distance Modem
A modem used to extend the range of the RS232 interface from
50 to 4000 feet.
Line Group Controller (LGC)
The Line Group Controller in the ISLU2 is responsible for
placing the switched information on the Line Interface Data
Bus (LIDB). Each LGC has two LIDBs, one to each Service
Group. The LGC can also provide concentration, since only 44
time slots are available for switched information. The group of
32 BRIs or cards is connected to a Line Group Controller (LGC)
by a Duplicated Group Interface Data Bus (GIDB). In an
ISLU2, you can have a maximum of 16 LGCs equipped with 32
BRIs (512 customer terminations).
Line Interface Data Bus (LIDB)
A 32 time slot bus to connect the Line Group Controller and the
Common Data boards in an ISLU2.
Link A physical or electrical connection between two end points; for
communications purposes, may consist of one or more channels.
GLOSSARY 235-200-150
May 2003
Page G-6 Issue 3.00
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