User`s guide

56K Professional Message Modem42
buffer
A memory area set aside to be used as temporary storage during input
and output operations. An example is the modem's command buffer.
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; 640KB 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.