THE BASICS in Computer Communications Terminology (in rather descriptive
terms)

Bits per second - The number of binary bits per second that are
transferred through a communications path or component; bit/s and bps
are used interchangeably in the literature to denote this quantity; also
note that 1000 = kilo (k); 1,000,000 = mega (M); 1,000,000,000=giga (G);
for example, 1Gbps = 1,000,000,000 bits per second.

Signal Propagation - The movement of the signal over its transmission
path is referred to as signal propagation.

Propagation Delay - There is always a short but finite time delay for a
signal (electrical, optical, or radio) tp propagate (travel) from one
end of a transmission medium to another. At best signals propagate
through free space at the speed of light (3*10**8m/sec); in contrast,
the speed of propagation through twisted pair wire or coax is 2/3 of
this value. Although this may seem insignificant, in some situations
this delay is important!

Analog Data Transmission - The information content (of the digital
signal) has to be carried by an analog waveform which is suitable for
transmission over the particular channel.

Modulation - This simply means that the data stream changes or modulates
the signal on the communications path (channel or link); alternatively,
changing the carrier wave in sympathy with an information signal.
However, it is common to refer to the various schemes used for
transmitting digital data by the terms amplitude shift keying, frequency
shift keying, or phase shift keying.

Amplitude - indicates the signal level and the amount of negative or
positive voltage.

Frequency - indicates the rate (in hertz) of the signal oscillation.

Bandwidth - the range of transmission frequencies that can be (are)
carried on a communications line (i.e. the high-end frequency minus the
low-end frequency).

Signaling rate (baud) - The number of line signal transitions per second
(in baud); rate of signal change on the line.

Multilevel transmission - methods to transmit more than 1 bit per  baud.

Attenuation - signal gets weaker with propagation.

Dispersion - signal spreads with propagation.

Distortion - signal changes shape.

Noise - "Random" interference added to signal.

Simplex Transmission - Data flows in only one direction.

Half-Duplex  Transmission - Data flows in both directions, but, in only
one direction at a time.

Full-Duplex (or simply duplex)  Transmission - Simultaneous transmission
in both directions.