Multitech MultiModem MT5634ZPX User Manual page 57

N
Network: A group of computers connected by cables or other
means and using software that enables them to share equipment,
such as printers and disk drives to exchange information.
Node: Any point within a network which has been assigned an
address.
O
OHCI (OpenHCI): Open Host Controller Interface Specification for
USB. All transfers on the USB are initiated by the host system's
host controller. The host controller is responsible for controlling
traffic on the USB and can be appropriately programmed to
transfer data to and from USB devices. This is typically a PCI
device that can be programmed to run a given schedule of
transfers on the USB and bus master the results into memory for
processing by the host software. There are currently two
standards for host controllers: OpenHCI (OHCI or Open Host
Controller Interface) and UHCI (Universal Host Controller
Interface). Both these standards define register level interfaces of
the host controller to PCI bus. Bandwidth allocation over the USB
is software managed and is done by the programming of the host
controller.
Object-Oriented: A method for structuring programs as
hierarchically organized classes describing the data and
operations of objects that may interact with other objects.
Office Channel Unit - Data Port (OCU-DP): The CO channel
bank used as the interface between the customer's DSU and the
channel bank.
Off-hook: The condition of a device which has accessed a phone
line (with or without using the line). In modem use, this is
equivalent to a phone handset being picked up. Dialing and
transmission are allowed, but incoming calls are not answered.
Contrast "on-hook".
Off Premise Extension (OPX): An extension or phone that
terminates in a location other than that of the PBX. Commonly
used to provide a corporate member with an extension of the PBX
at home.
Ones Density: The measure of the number of logical 1s on a T1
line compared to a given total number of bits on that line; used for
timing information in data recovery in AMI and B8ZS.
On-Hook: The condition of a device which has not accessed a
phone line. In modem use, this is equivalent to a telephone
handset that has not been picked up. In other words, it can receive
an incoming call. Contrast "off-hook".
Open Shortest Path First (OSPF): A hierarchical Interior
Gateway Protocol (IGP) routing algorithm for IP that is a proposed
standard for the Internet. OSPF incorporates least-cost routing,
equal-cost routing, and load balancing.
Outage: The measure of the time during which a circuit is not
available for use due to service interrupt. Outage is the
complement of circuit "availability" (100% minus % available = %
outage).
Out-of-band: Signaling that is separated from the channel
carrying the information (e.g., the voice/data/video signal is
separate from the carrier signal). Dialing and various other
"supervisory" signals are included in the signaling element.
Contrast "In-band" signaling.
Out of Frame (OOF): A T1 alarm condition that is logged on the
loss of 2, 3 or 4 of 5 consecutive FT framing bits.
Multi-Tech Systems, Inc. MT5634ZPX User Guide
P
Packet: 1. In data communication, a sequence of binary digits,
including data and control signals, that is transmitted and switched
as a composite whole. The data, control signals and, possibly,
error control information are arranged in a specific format. 2.
Synonymous with data frame. 3. In TCP/IP, the unit of data passed
across the interface between the Internet layer and the link layer. A
packet includes an IP header and data. A packet can be a
complete IP datagram or a fragment of an IP diagram. 4. In X.25,
a data transmission information unit. A group of data and control
characters, transferred as a unit, determined by the process of
transmission. Commonly used data field lengths in packets are
128 or 256 bytes. 5. The field structure and format defined in the
CCITT X.25 recommendation.
Packet Assembler/Dissembler (PAD): Used by devices to
communicate over X.25 networks by building or stripping X.25
information on or from a packet.
Packet Data: The information format ("packetized") used for
packet-mode calls.
Packet Mode: Refers to the switching of chunks of information for
different users using statistical multiplexing to send them over the
same transmission facility.
Parity bit: An extra bit attached to each byte of synchronous data
used to detect errors in transmission.
Permanent Virtual Circuit (PVC): A connection between two
endpoints dedicated to a single user. In ISDN, PVCs are
establised by network administration and are held for as long as
the user subscribes to the service.
Physical Unit (PU): The component that manages and monitors
the resources (such as attached links and adjacent link stations)
associated with a node, as requested by an SSCP via an SSCP-
PU session. An SSCP activates a session with the physical unit in
order to indirectly manage, through the PU, resources of the node
such as attached links. This term applies to type 2.0, type 4, and
type 5 nodes only.
Pipe: A logical abstraction representing the association between
an endpoint on a device and software on the host. A pipe has
several attributes; for example, a pipe may transfer data as
streams (Stream Pipe) or messages (Message Pipe).
Plug and Play (PnP): A technology for configuring I/O devices to
use non-conflicting resources in a host. Resources managed by
Plug and Play include I/O address ranges, memory address
ranges, IRQs, and DMA channels.
Point of Presence (POP): The central office's end points of the
long distance carriers.
Point-to-Point Protocol (PPP): A protocol that lets a PC user
access TCP/IP (Internet memeber) using an ISDN terminal
adapter or a high-speed modem over a standard phone line.
Polling: Asking multiple devices, one at a time, if they have any
data to transmit.
Port: Point of access to or from a system or circuit. For Universal
Serial Bus, the point where a Universal Serial Bus device is
attached.
Primary Rate Interface (PRI): Used on ISDN. In North America,
and Japan, PRI is one 64Kbps D channel and 23 B channels.
Elsewhere, it is one D channel and 30 B channels.
Primitive: An abstract representation of interaction across the
access points indicating that information is being passed between
the service user and the service provider. The OSI Reference
Model defines four types of primitives: Request, Indication,
Response and Confirm.
Private Branch Exchange (PBX): A phone exchange located on
the customer's premises. The PBX provides a circuit switching
facility for phone extension lines within the building, and access to
the public phone network. See also "Exchange".
Glossary
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