GLOSSARY
105
carrier
The basic signal altered or modulated by the modem in
order to carry information.
character
A representation, coded in binary digits, of a letter,
number, or other symbol.
characters per second (CPS)
A data transfer rate generally estimated from the bit rate
and the character length. For example, at 2400 bps, 8-bit
characters with start/stop bits (for a total of ten bits per
character) will be transmitted at a rate of approximately
240 characters per second (cps). Some protocols, such as
error-control protocols, employ advanced techniques such
as longer transmission frames and data compression to
increase cps.
class 1 and 2.0
International standards used by fax application programs
and faxmodems for sending and receiving faxes.
cyclic redundancy checking (CRC)
An error-detection technique consisting of a test
performed on each block or frame of data by both sending
and receiving modems. The sending modem inserts the
results of its tests in each data block in the form of a CRC
code. The receiving modem compares its results with the
received CRC code and responds with either a positive or
negative acknowledgment.
data communications
The transmission or sharing of data between computers via
an electronic medium.
data compression table
A table containing values assigned for each character
during a call under MNP5 data compression. Default
values in the table are continually altered and built during
each call: The longer the table, the more efficient
throughput gained.