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NAI

See network access identifier (NAI).

nail up

To make a permanent, dedicated assignment, as in nailing up a connection. Typically, a nailed up connection cannot be dynamically modified during an application's runtime, but can be changed by re-initializing the hardware and/or the application.

NCC stack mode

An AG ISDN protocol stack mode in which the ISDN protocol stack implements all OSI layer 2 and layer 3 functionality. A channelizer is also present. AG ISDN TCP instances communicate with the application and with the channelizer entity in the protocol stack. See also ACU stack mode, LAPD stack mode, layer, TCP.

NDIS

Network Driver Interface Specification; a device driver specification that provides hardware independence and protocol independence for network drivers so that multiple protocol stacks can coexist in the same host-based application.

negotiation

In fax technology, a phase of the T.30 fax transmission protocol in which the two Group 3 fax machines exchange capabilities and determine the capabilities to use to transfer data.

Net Characterizer (NetChar)

A Fusion software utility that tests the effects of a variety of network conditions on voice data transmission.

network

In telephony, short for the telephone switching network. See also PSTN.

In information technology, a series of points or nodes interconnected by communication paths. Networks can interconnect with other networks and contain subnetworks. See also intranet, LAN, WAN.

network access identifier (NAI)

A software handle used to refer to a trunk.

network delay

The difference between the time at which the packet is offered to the network protocol stack by the application at one gateway, and the time at which the complete and error free packet is released from the network protocol stack to the application at the other gateway.

network layer

In the OSI protocol layering model, the network layer (layer 3) is the layer above the data link layer. Protocols for this layer describe methods for transferring information between computers. They also describe how data is routed within and between networks. One protocol used at this layer for ISDN applications is CCITT recommendation Q.931. See also data link layer, Q.931.

network rate

Most data networks can carry a bandwidth far greater than that needed for fax delivery. In the case where a network has a very slow speed link, the maximum bandwidth on this link can be called the network rate. If this rate is less than 9600 bps, the network rate may impose the determining limit on the maximum data rate of a fax session.

NFAS

Non-FAcility Signaling; an AG ISDN stack mode in which a single D channel on a T1 trunk carries the signaling for all B channels on more than one trunk. This leaves the 24th channels on the trunks free for use as B channels. NFAS is not supported on E1 trunks. See also ACU stack mode, B channel, D channel, LAPD stack mode, NCC stack mode, T1.

NIC

Network Interface Card; an adapter card that enables a network cable to be connected to a computer. The NIC includes encoding and decoding circuitry, and an input for a network cable connection.

NMS

Natural MicroSystems Corporation.

NMS ADPCM

A form of ADPCM that requires less processing power than the CCITT standard and provides equivalent voice quality. See also ADPCM, PCM.

NMS TSP

A TAPI telephony service provider (TSP) provided with AG TAPI that supplies the interface between TAPI and AG telephony hardware. See also TSP.

NMS WAVE

A WAVE driver provided with AG TAPI that supplies the interface between the Windows Multimedia System and AG telephony hardware.

NOCC

NO Call Control; the trunk control program used when the application will not use protocol-independent call control. NOCC is a stateless protocol which does not generate any call control events. It is typically used with low-level functions to perform call control from the host. Also known as the NULL protocol. See also protocol (telephony), TCP.

noise suppression threshold

Noise level below which signals from a conference seat to a conference are ignored.

non-blocking system

A switching system with enough switching capability to allow all possible sets of connections to be made. See also blocking system.

Non-Exclusive Mode

One of two modes which determine what the ISDN TCP does if the network denies the ISDN TCP use of its default channel. The default channel is the B channel bound to the same CTA context as the ISDN TCP instance. In Non-Exclusive Mode, the TCP will accept any B channel that the network assigns. See also default channel, Exclusive Mode.

non-RTP means

Protocols and mechanisms that may be needed in addition to RTP to provide a usable service. In particular, for multimedia conferences, a conference control application may distribute multicast addresses and keys for encryption, negotiate the encryption algorithm to be used, and define dynamic mappings between RTP payload type values and the payload formats they represent, for formats that do not have a predefined payload type value. For simple applications, electronic mail or a conference database may also be used. See also RTP, RTP payload.

Non-Standard Facilities Frames

The Group 3 fax standard, ITU T.30, allows non-standard frames (a frame with contents that are not specified by T.30) to be transmitted with most negotiations. A non-standard frame begins with the country code of the manufacturer, the manufacturer's code, and any additional ASCII information (limited by allowable transmission time of three seconds). The non-standard frame transmitted by a remote fax terminal will only be read if the first three bytes match the country code and manufacturer's ID parameters for the local fax terminal. T.30 defines the following terms for non-standard frames:

• NSF (Non-Standard Facilities), a frame sent in response to the called fax terminal's DIS frame
• NSS (Non-Standard Set Up), a frame sent by the called fax terminal in response to the calling fax terminal's DCS frame (the DCS frame was sent in response to the called fax terminal's DIS frame).
• NSC (Non-Standard facilities Command), a frame sent by the calling fax terminal to command the called fax terminal to send (a poll).

NSC

Non-Standard facilities Command frame; a non-standard frame as specified by the ITU T.30, the Group 3 fax standard, sent by the calling fax terminal to command the called fax terminal to send (a poll).

NSF

Non-Standard Facilities frame; a non-standard frame as specified by the ITU T.30, the Group 3 fax standard, sent by the calling fax terminal in response to the called fax terminal's DIS frame. See also DIS.

NSS

Non-Standard Set Up frame; a non-standard frame as specified by the ITU T.30, the Group 3 fax standard, sent by the called fax terminal in response to the calling fax terminal's DCS frame (the DCS frame was sent in response to the called fax terminal's DIS frame).

NT1

Network Terminating equipment, class 1; an ISDN equipment category. Equipment in this category physically terminates the local loop.

NT2

Network Terminating equipment, class 2; an ISDN equipment category.