Verilink AS2000: The Basics (880-502981-001) Product Manual - Manual (Page 156)

Acronyms and Definitions
Glossary-36 Verilink Access System 2000: Basics
O
off-hook The condition indicating the active
state of a voice circuit.
OID Object identifier—the address of a
Management Information Base
(MIB) variable.
ones density The requirement for digital
transmission lines in the public
switched telephone network that
eight consecutive zeros cannot
exist in a digital transmission.
There are different ones density
algorithms available to ensure that
enough ones are included in the
bit stream. Required with T1
alternate mark inversion (AMI)
line coding.
on-hook The condition indicating the
inactive state of a voice circuit.
on-line When a device is actively
connected to a network.
OOF See out-of-frame (OOF) .
Open System Interconnection (OSI) Developed by the ISO, the only
internationally standardized
framework for communication
between different systems made
by different vendors.
OSI See Open System
Interconnection (OSI) .
out-of-frame (OOF) A condition when any two of four
or two of five consecutive frame
bits received from the network line
are incorrect or lost. The CSU
attempts to reframe. User data is
lost during an OOF condition.
out-of-frame second (OOFS) A second during which an out-of-
frame (OOF) condition exists.
out-of-service (OOS) Equipment removed from service.