User`s guide

24
Asynchronous Transmission
Data transmission in which the length of time between transmitted characters may vary. Because the time lapses
between transmitted characters are not uniform, the receiving modem must be signaled as to when the data bits of
a character begin and when they end. The addition of Start and Stop bits to each character serves this purpose.
Auto Answer
Sets the modem to pick up the phone line when it detects a certain number of rings. See S-register (S0) in
Technical Quick Reference.
Auto Dial
A process where your modem dials a call for you. The dialing process is initiated by sending an ATDT (dial tone) or
ATDP (dial pulse) command followed by the telephone number to dial. Auto Dial is used to dila voice numbers.
See command Dn.
Baud Rate
A term used to measure the speed of an analog transmission from one point to another. Although not technically
accurate, baud rate is commonly used to mean bit rate.
Binary Digit
A 0 or 1, reflecting the use of the binary numbering system (only two digits). Used because the computer
recognizes either of two states, OFF or ON. Shortened form of binary digit is bit.
Bit Rate
Also referred to as transmission rate. The number of binary digits, or bits, transmitted per second (bps).
Communications channels using telephone channel modems are established at set bit rates, commonly 300, 1200,
2400, 4800, 9600, 14.400 and higher.
Bits Per Second (BPS)
The bits (binary digits) per second rate. Thousands of bits per second are expressed as kilobits per second or
kbps.
Buffer
A memory area used as temporary storage during input and output operations. An example is the modem's
command buffer.