User`s guide

User’s Guide 37
byte
A group of binary digits stored and operated upon as a unit. In user
documentation, the term usually refers to 8-bit units or characters.
One kilobyte (KB) is equal to 1,024 bytes or characters; 640 KB
indicates 655,360 bytes or characters.
carrier
A tone signifying a connection the modem can alter to communicate
data across telephone lines.
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 between 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
A type of communications in which computers are able to exchange
data over an electronic medium.