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Appendix A

Glossary


AIS
Alarm Indication Signal; a signal that replaces the normal traffic signal when a maintenance alarm indication has been activated. An AIS is transmitted downstream indicating that an upstream failure has occurred. See also blue alarm, red alarm, yellow alarm.

Alarm Indication Signal
See AIS.

BIOS
Basic Input/Output System; on PC-compatible computers, the set of essential software routines that test the hardware at setup, launch the operating system, and support the transfer of sata between hardware systems.

blue alarm
One of the three alarms to indicate problems with T1/E1 transmissions. The blue alarm occurs when two consecutive frames have fewer than three zeros in the data stream. A blue alarm sends ones in all bits of all timeslots. Also known as the AIS. See also AIS, red alarm, yellow alarm.

CEPT
Conference of European Postal and Telecommunications administrations; a European telephony standards committee.

CEPT E1
A standard used in Europe for digital telephone carriers. CEPT E1 is similar to T1 but operates at 2.048 Mbps and has 32 channels instead of T1's 24. See also T1.

channel
An electronic communications path. In digital telephony, a channel usually refers to a separate connection carried on a digital trunk.

Communications Processor
See CP.

CompactPCI
A PICMIG hardware standard which is electrically identical to standard PCI and based on the mechanical form factor of VME to provide a rugged, industrial package. Individual cards conform to the VME 6U height. CompactPCI can provide high availability through hot swap. See also hot swap, PCI, PICMG.

CP
Communication Processor; a separate processing engine that offloads processing from the main CPU of a system to another CPU that is specialized for a certian task. For TX hardware environments, the CP allows the system to offload Communications/Protocol processing onto the TX board.

CPCON
A host-based utility that provides a user interface to the Kernel. This utility presents a line-oriented operator console to any CP. See also CP, KERNEL.

CPLOT
Utility program which downloads the executable code and configuration data onto the TX board.

CSA
Canadian Standards Association; CSA certification is required for most electrical equipment used in Canada.

CSU
Channel Service Unit; a device connecting customer T1 equipment and a network line. See also T1.

D4 framing
A framing format in the T1 environment. The D4 framing bit is used to identify both the channel and the signaling frame. In D4 framing, signaling for voice channels is carried in-band along with the encoded voice. A pattern derived from the framing bit of each individual frame is used to maintain synchronization. See also robbed-bit signaling.

device driver
Software which translates the application commands into the code required by the device.

DLL
Dynamic Link Library; a library of software object modules that can be loaded and accessed on demand.

DRAM
Dynamic Random Access Memory chip; RAM memory that requires data to be refreshed periodically to prevent its loss in memory. See also SRAM.

DSX-1
Digital Signal Cross-Connect [X] Level 1; A standard set of parameters for cross-connecting DS-1 lines.

duplex
See full-duplex, half-duplex, simplex.

Dynamic Random Access Memory
See DRAM.

E1
See CEPT E1.

ESF
Extended SuperFrame; a framing format in the T1 environment. There are 24 separate 193 bit frames in an Extended Superframe. The 24 framing bits, one from each individual frame, are used to maintain synchronization in a manner similar to D4 framing, provide error checking, and provide a diagnostic channel. In-band signaling is employed using robbed-bit signaling. See also D4 framing, robbed-bit signaling, T1.

Ethernet
A local area network hardware, communication, and cabling standard. Ethernet is synonymous with 10Base-T.

ETSI
European Telecommunication Standards Institute.

Fast Ethernet
An Ethernet specification that enables data transmission rates of 100 Mbit/s. Synonymous with 100Base-T.

firmware
Software routines stored in read-only memory (ROM), such as startup routines and low-level input/output instructions.

frame (T1/E1)
A portion of a PCM data stream that contains one binary data word, typically 8 bits, for each unidirectional channel. A frame usually will also contain control and synchronization bits. Each frame is 125 microseconds long.

full-duplex
Simultaneous two-way voice or two-way signal data transmission. See also half-duplex, simplex.

Full Hot Swap
A system model requiring Full Hot Swap boards on a CompactPCI platform. Full Hot Swap boards include a blue LED for Hot Swap signaling and switches in the ejector handles to control the hardware state of the board. See also hot swap.

ground
An electrical connection to earth or to a common conductor which is connected to earth.

H.110 bus
The Telephony bus which is a specific implementation of the H.100 bus streams and clocks, but redefines CT_NETREF as CT_NETREF_1 and adds CT_NETREF_2. It is implemented on a CompactPCI backplane at the J4 location. See CompactPCI, J1, J2, J3, J4, J5.

half-duplex
A circuit that can carry information in both directions, but can only use one direction at a time. See also full-duplex, simplex.

host
The PC on which an application runs. Also used to designate a computer with full two-way access to a network such as local area network or the Internet.

hot swap
Ability to perform "live" insertion and removal of hardware components without disrupting the host system or application.

IETF
Internet Engineering Task Force; an Internet technical standards organization.

Instance ID
For TX environments, uniquely defines the process which is handling the call. Applications running on a host always have an Instance ID of zero.

International Telecommunications Union
See ITU.

Internet Engineering Task Force
See IETF.

ISA
Industry Standard Architecture; the de-facto bus card standard in the IBM-PC compatible world. Also known as the PC/AT bus.

ISUP
ISDN User Part; the SS7 protocol layer which allows for the establishment, supervision, and clearing of circuit-switched connections between two SS7 signaling points, such as central office switches. Despite its name, the ISUP layer is not unique to ISDN connections - it is used to manage all types of circuit-switched connections.

ITU
International Telecommunications Union; an international standards body for telecommunications.

J1, J2, J3, J4, J5
Connector positions on the NMS CompactPCI boards. The connectors are numbered sequentially from bottom to top, with J1 assigned to the lowest connector. As specified in PICMG 2.5, R1.0, the following connector assignments are used by the TX 3220C board:

See also CompactPCI, PICMG.

KERNEL
The operating system loaded onto a Communications Processor on a TX board.

keying
A system of mechanical interlocks which restrict the insertion of a CompactPCI board unless they are configured for a specific board and host. Keying is factory-configured and cannot be modified by an end-user.

MTP
Message Transfer Part; the SS7 protocol layers responsible for the reliable, in-sequence delivery of packets between two SS7 signaling points. The MTP's functions include message routing, signaling link management, signaling route management, and congestion control.

multiplex
To transmit more than one signal or channel over a single physical circuit.

NMS
Natural MicroSystems Corporation.

PCI
Peripheral Component Interconnect; a 32/64 bit local bus inside a PC. See also CompactPCI.

PICMG
PCI Industrial Computer Manufacturers Group; an industry consortium which defined the CompactPCI standard, and other technical specifications such as hot swap. See also CompactPCI, hot swap.

red alarm
One of the three alarms that indicate problems with T1 transmissions. A red alarm is generated for a locally detected failure, such as loss of synchronization for 2.5 seconds. See also AIS, blue alarm, yellow alarm.

redundancy
A feature of the SS7 3.0 software that enables a system to detect and recover from the failure of signaling links on a TX SS7 board, the failure of a signaling node, or the failure of the TX SS7 board itself. See also SS7, TX.

ring
The alerting signal to the subscriber or terminal equipment; also the name for one conductor of a wire pair, designated by R. The other is called tip, or T. See also tip.

RJ-48C
An 8-position keyed plug most commonly used for connecting T-1 circuits.

robbed-bit signaling
A signaling method that uses the least significant bit of each timeslot in every sixth frame to carry signaling information (on-hook, off-hook, etc.) for that voice channel. See also D4 framing.

SCCP
Signaling Connection Control Part; an SS7 protocol that provides both connection-oriented and connectionless data transfer over an SS7 network. It extends the service provided by the SS7 MTP layers by adding extended addressing capabilities and multiple classes of service. The SCCP addressing capabilities allow a message to be addressed to an individual application or database within a signaling point. See also SS7.

Signaling System 7
See SS7.

simplex
A circuit which carries information in only one direction. See also full-duplex, half-duplex.

snapshot
In the TX environment, a dump file, usually named cpsnap.dmp, that a user can create to assist in the diagnosis of internal CP operations. The snapshot file is an image of every byte of memory on the CP at the time of snapshot.

span line
A T1 line. Also known as a T1 trunk, or as a span.

SRAM
Static Random Access Memory; RAM that retains its data without the refreshing required by DRAM. SRAM offers faster memory access time and is more expensive than DRAM. See also DRAM.

SS7
Signaling System 7; an out-of-band signaling system that provides fast call setup (using circuit-switched connections) and transaction capabilities for remote database interactions.

Static Random Access Memory
See SRAM.

T1
A standard for telephone transmission that multiplexes 24 digital voice channels on a single 1.544 Mbyte/s carrier.

TCAP
Transaction Capabilities Application Part; an SS7 protocol that provides applications with transaction support over the SS7 network. It enables the exchange of non-circuit related data, such as database queries/responses and remote feature invocation requests, between SS7 signaling points. The TCAP layer relies on both the MTP and SCCP layers for message addressing and delivery.

Telephone User Part (TUP)
Like the ISDN user part, the telephone user part is an SS7 protocol that allows for the establishment, supervision, and clearing of circuit-switched connections between two SS7 signaling points, such as central office switches. It is used primarily in parts of Asia, South America, and Latin America. Use of TUP is decreasing as it is replaced by ISUP for circuit switching in most parts of the world.

tip
One conductor of a wire pair, designated by T; usually connected to the positive side of a line circuit. The other is called ring, or R. See also ring.

trunk
A transmission channel connecting two switching machines.

With regard to NMS products, a trunk is defined as the physical interface between the telephone network and the board. It can be used interchangeably with line because it could be connected to either a trunk or a line.

TX
Natural MicroSystems' product line of telephony and signaling hardware/software.

uninterruptable power supply
See UPS.

UPS
Uninterruptable Power Supply; a device, connected between a computer (or other electronic equipment) and a power source (usually an outlet receptacle), that provides a consistent electrical flow to the computer.

yellow alarm
One of the three alarms to indicate problems with T1 transmissions. A yellow alarm signal is sent back toward the source of a failed transmit circuit in a T1 transmission path. A yellow sends zeros in bit two of all timeslots. See also AIS, blue alarm, red alarm.



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