Multitech MT5634HD16 User Manual page 64

MT5634HD8/16 User Guide
A
AC (Alternating Current): A power source whose signal
crosses a reference voltage (usually called ground or zero).
Alternating between a maximum and minimum voltage, AC
may also be referred to as a bi-polar signal. Contrast with
DC.
ACK (ACKnowledgment code – pronounced "ack"): A
communications code sent from a receiving modem to a
transmitting modem to indicate that it is ready to accept
data. It is also used to acknowledge the error-free receipt of
transmitted data. Contract with NAK.
ACS (Asynchronous Communications Server): A
communications server that managers a pool of modems for
shared use over the LAN. It directs outgoing messages to the
next available modem and directs incoming messages to the
appropriate workstation. It also provides conversion
between LAN packets and asynchronous format.
Address: A numbered location inside a computer. It's how
the computer addresses its resources, like a video card, serial
ports, memory, etc.
Algorithm: A set of ordered steps for solving a problem.
This can be a mathematical formula or the instruction in a
computer program.
Alphanumeric: The basic character set which includes the
letters A to Z (and a to z) and the digits 0 to 9.
Amplitude: The difference between the maximum and
minimum voltages of a waveform expressed as a "peak-to-
peak" voltage.
Amplifier: An active device within a circuit which increases
the voltage level of all signals (desirable and undesirable).
Analog loopback: A modem diagnostic used to test either
the local analog loop (the modem's internal circuitry) or the
remote analog loop (the telephone line). The local analog
loop test is accomplished by activating the self-test mode
and tying the modem's modulator to its demodulator and
examining the return stream of data at the PC or terminal it
services. The remote analog loopback can only be activated
on four-wire leased line connections with a remote modem
capable of performing the same test.
Analog signal: A waveform which has amplitude, frequency
and phase, and which takes on a range of values between its
maximum and minimum points. Analog implies continuous
movement from point A to point B, as opposed to discrete
jumps. For example, sound is continuously varying air
vibrations and is converted into analogous electric signals to
be carried on a telephone line.
Analog Transmissions: One of two types of
telecommunications which uses an analog signal as a carrier
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of voice, data, video, etc. An analog signal becomes a carrier
when it is modulated by altering its phase, amplitude and
frequency to correspond with the source signal. Compare
with digital transmission.
ANSI (American National Standards Institute –
pronounced "ansy"): A U.S. standards organization
supported by over 1000 companies and trade organizations.
It is a non-profit, non-government group that is the U.S.
member of the ISO (International Standards Organization).
ANSI character set: An 8-bit character set that contains 256
characters. The first 128 characters are alphanumeric and
the second 128 contain math and foreign language symbols.
API (Application Programming Interface): The language
and message format used by a program to activate and
interact with functions in another program or in the
hardware. A software module which provides a uniform
interface for otherwise incompatible programs.
ASCII (American Standard Code for Information
Interchange – pronounced "askey"): A binary code for
data that is used in communications and in many computers
and terminals. The code is used to represent numbers,
letters, punctuation and control characters. The basic ASCII
code is a 7-bit character set, which defines 128 possible
characters. The extended ASCII file provides 255 characters.
Associate: Establishing that all files with a given extension
are usable by a certain application.
Asynchronous Transmission: The transmission of data in
which each character is a self-contained unit with its own
start and stop bits. This is a common method of
transmission between a computer and a modem. One
character at a time, encoded into a series of electrical pulses,
is transmitted or received. This is the oldest method of data
transfer. When it is used with error correcting software and
data compression algorithms, along with the increase it
maximum attainable speeds, it continues to be a viable
alternative to synchronous transmission.
ATM (Asynchronous Transfer Mode): A high speed
switching technique suitable for MAN's (Metropolitan Area
Network) and broadband ISDN transmission.
Auto Answer: A modem feature which enables the modem
to "off-hook" when it detects an incoming call.
Auto Dial: Some modems provide this feature for
asynchronous dialing. This feature is a pre-defined macro
that allows the user to enter the location of a phone number
(i.e. N0 through N9) and have the modem go off-hook, dial
and establish the connection. With the auto dial feature, an
asynchronous terminal can establish a dialing directory
without running a communication software package.
CommPlete Communications Server