Glossary
Glossary-7
3170-A2-GB20-20
December 1996
power-up self-test
A test that checks most hardware components when power is applied to the device
or a reset is initiated.
PPP
Point-to-Point Protocol. A link layer protocol used by SNMP.
PRBS
Psuedo-Random Bit Sequence. A test pattern containing any possible combination
of digital ones and zeros for a given string length.
primary clock
The primary timing source used to synchronize all of the E1 and data port interfaces
on the E1 DSU/CSU.
PRM
Performance Report Message. A message indicating performance data such as
errored seconds, unavailable seconds, etc.
protocol
A set of rules that determines the behavior of functional units in achieving
communication.
Ptrns branch
Test Patterns branch of the E1 DSU/CSU menu tree.
pulse density
A measure of the number of “ones” (marks, pulses) in relation to the total number
of bits transmitted.
QRSS Test
Quasi-Random Signal Test. A test pattern simulating a random pattern of digital
ones and zeros used to simulate normal transmission.
RAI
Remote Alarm Indication. A remote alarm on an E1 line.
RAM
Random-access memory. Read/write memory that is volatile and loses its contents
when power is removed.
register
A part of the device’s memory that holds stored values.
Rel branch
Release branch of the E1 DSU/CSU menu tree.
reset
A reinitialization of the E1 DSU/CSU that occurs at power-up or in response to a
reset command.
RFC
Request for Comments. The set of documents that describes the standard
specifications for the TCP/IP protocol suite.
RIP
Routing Information Protocol. A protocol used to add routes in the Internet.
RJ48C
An 8-position modular connector.
RLB
Repeater Loopback. Loops the signal being sent to the network back to the DTE
Drop/Insert and data ports after it has passed through the framing circuitry of the E1
DSU/CSU.
Rlpbk branch
Remote Loopback branch of the E1 DSU/CSU menu tree.
router
A device that connects LAN segments.
RS-232
An EIA standard for a low-speed, 25-position, DCE/DTE interface.
RS-232-like MIB
Defines objects for managing RS-232-type interfaces (e.g., RS-422, RS-423, etc.)
and supports synchronous data ports and management communication ports on the
E1 DSU/CSU.
RS-449
An EIA standard for a general-purpose, 37-position, DCE/DTE interface.
RTS
Request-to-Send. V.24 circuit 105.
RX
Receive. To obtain signals that have been transmitted.
RXC
Receive Clock. V.24 circuit 115.
RXD
Receive Data. V.24 circuit 104.
secondary clock
The secondary clock source used to provide timing to the E1 DSU/CSU when the
primary clock fails.
