Motorola and V.32bis, V.34-SDC, 326X V.34 manual Pstn

Modulation	Systematic changing of properties (e.g., amplitude, frequency, phase) of an analog signal to
	encode and convey digital information.
MNP	Microcom Networking Protocol. An asynchronous communications protocol that provides
	error correction.
Multiplexer	(1) Any multiport device that allows two or more users to share a common physical
	transmission channel; employed in pairs, one at each end of the channel, where each device
	performs both multiplexing of the multiple user inputs and demultiplexing of the channel
	back into the separate user data streams. (2) A device that allows two or more analog data
	signals to be transmitted simultaneously over a single telephone line.
Off-hook	The description for when a telephone or modem connects to the dial line and presents
	electrical characteristics, similar to when a telephone handset is removed from the cradle.
Parity bit	An error-checking mechanism for asynchronous transmission. An additional nondata bit
	added to a group of bits, that indicates whether the number of 1’s in the group is odd or even.
PBX	Private branch exchange. A telephone switching system located on a customer’s premises.
Phase jitter	The deviation in phase of the transmitted analog signal from its timing signal; often caused
	by alternating current components in a telecommunications network. It is continuous,
	long-term, and often nearly constant in frequency and severity.
Point-to-point	A line that directly connects two end points (e.g., a remote location to a host computer);
	opposite of multipoint.
Port	A connector and associated circuitry enabling digital data to be injected into or retrieved
	from a communications network.
Protocol	Formal set of rules governing the format, timing, sequencing, and error control of
	exchanged messages on a data network.
PSTN	Public Switched Telephone Network.
PTT	Postal Telegraph and Telephone. Government authority (in many European companies) that
	typically operates the public telecommunications network, sets standards and policies, and
	negotiates communications issues internationally for a particular country.
QAM	Quadrature Amplitude Modulation. A type of modulation that varies both the phase and
	amplitude of an analog wave.
RS-232-D	See EIA/TIA 232-D.
RTS	Request To Send. The signal from a terminal to its co-located modem that prepares the
	modem for data transmission.
SDC	See Synchronous Data Compression.
SDLC	Synchronous data link control; bit-oriented protocol developed by IBM.
Start bit	A data bit used in asynchronous transmission to signal the beginning of a character.
Stop bit	A data bit used in asynchronous transmission to signal the end of a character.
STX	Start of text control character. Designates the start of a message's text as well as (usually) the
	end of the message heading.

Glossary

Glossary-5