Multi-Tech ISIHI-2S Specifikace stáhnout pdf (Strana 182)

182 MultiModemISI Hybrid Series, ISIHI-2S/2U

Glossary

tone dialingOne of two methods of dialing a telephone,

usually associated with push button phones. Compare with

pulse dialing.

transistorA semiconductor device used to amplify a

signal, or open and close a circuit. In digital computers, it

functions as an electronic switch.

TSR (terminate and stay resident)A software program that

remains active and in memory after its user interface is

closed. Similar to a daemon in UNIX environments.

twisted pair wiringA type of cabling with one or more

pairs of insulated wires wrapped around each other. An

inexpensive wiring method used for LAN and telephone

applications, also called UTP wiring.

UART (universal asynchronous receiver/transmitter)A chip

that transmits and receives data on the serial port. It

converts bytes into serial bits for transmission, and vice

versa, and generates and strips the start and stop bits

appended to each character.

UNIXA multiuser, multitasking operating system, first

developed by AT&T in the 1970s. It now runs on a wide

variety of computer systems from micro to mainframe and

is controlled by UNIX System Laboratories (USL).

UTP (unshielded twisted pair)Telephone type wiring.

V.21The CCITT modulation standard for 300bps, full-

duplex transmission over dial-up lines.

V.22The CCITT modulation standard for 1200bps, full-

duplex transmission over a dial-up or 2-wire leased line.

This is not common in North America.

V.22bisThe CCITT modulation standard for 2400bps,

full-duplex transmission over a dial-up or a 2-wire leased

line.

V.23The CCITT modulation standard for 75/1200bps,

half-duplex transmission over dial-up lines. This is not

common in North America.

V.24The CCITT hardware interface specification for

interchange circuits between the DTE and DCE.

V.25bisA dialing command set developed by the CCITT

for both synchronous and asynchronous devices. Since

V.25bis does not provide any modem configuration

commands, it is primarily used for its synchronous dialing

commands, while the AT commands are used for asynchro-

nous dialing and for modem configuration.

V.26The CCITT modulation standard for 2400bps, full-

duplex transmission over 4-wire leased lines. Primarily for

synchronous use. Not common in North America.

V.27The CCITT modulation standard for 4800bps, full or

half-duplex transmission. Primarily for synchronous use.

Not common in North America. V.27ter is used by Group 2

fax-modems for 4800bps fax transmission.

V.29The CCITT modulation standard for 9600bps, 2-wire

(half-duplex) or 4-wire (full-duplex) transmissions,

primarily over leased lines (synchronous or asynchronous).

V.29 is used for Group 3 fax transmissions.

V.32The CCITT modulation standard for synchronous or

asynchronous input to be transmitted at 9600bps over the

PSTN. V.32 operates in half- or full-duplex mode.

V.32bisThe CCITT modulation standard for synchronous

or asynchronous input to be transmitted at 14,400bps over

the PSTN. V.32bis operates in half- or full-duplex mode.

V.32terboAn AT&T recommendation for synchronous or

asynchronous input to be transmitted at 14,400 bps over

the PSTN. V32terbo operates in half- or full-duplex mode.

V.32The CCITT modulation standard for synchronous or

asynchronous input to be transmitted at 9600bps over the

PSTN. V.32 operates in half- or full-duplex mode.

V.33A CCITT modulation standard for 14,400bps

synchronous transmission over a 40-wire leased line.

V.35The CCITT hardware interface specification com-

monly used by DSU/CSUs and other high-speed devices.

V.42A CCITT recommendation for error-control hardware

on a modem that accepts asynchronous input. V.42 recom-

mends for manufactures to implement LAP-M and makes a

provision for MNP-5 as a alternative because of its

popularity. Most modem makers provide both.

V.42bisA CCITT recommendation for data compressing

hardware on a modem that accepts asynchronous input.

V.42bis is based on a dynamically updated dictionary that

looks up common strings and replaces the strings with code

words. This reduces the amount of characters actually

transmitted. V.42bis has been found to be most effective for

file transfers that contain long strings of repetitive informa-

tion and least effective for short strings of unique data.

V.54The CCITT recommendation to standardize Bit Error

Rate Testing (BERT) and Loopback testing (Local Analog

and Digital Loopback, as well as Remote Analog and

Digital Loopback).

VRC (vertical redundancy check)An error checking

method that generates and tests a parity bit for each byte of

data that is moved or transmitted.

WAT S (Wide Area Telephone Service)A discounted long-

distance calling plan that allows calls in or out. The

popular 800 numbers are WATS lines in. The calls are

charges to the holder of the 800 number at a discounted

rate.

WorkstationTraditionally, a dumb terminal connected to a

host. However, with the advent of LANS and WANS, PCs

that are connected to a LAN are now called workstations

too, even though they are capable of independent process-

ing. A workstation is simply an input/display device

through which a user accesses a resource.

X.121CCITTs recommendation for unique addressing of

each DTE connected to a communications network

throughout the world. X.121 uses fifteen digits: a one-digit

prefix, a four-digit DNIC number (which identifies the

1 2 ... 177 178 179 180 181 182 183 184 185 186 187 188

Komentáře k této Příručce

Žádné komentáře

Multi-Tech ISIHI-2S Specifikace Strana 182

Komentáře k této Příručce

Související produkty a manuály pro Sítě Multi-Tech ISIHI-2S