Apple GeoPort Telecom Adapter Kit - Manual (Page 77)

O
odd parity Use of an extra bit set to 0 or 1 as necessary to
make the total number of 1 bits in a character an odd
number. For example, the 7-bit ASCII code for the letter A
(1000001) has two 1 bits; for odd parity, the transmitting
device appends an eighth bit equal to 1 (11000001) so that
the total number of 1 bits remains odd. The receiving device
can count 1 bits as a way of checking for transmission errors.
off-hook Your equipment takes control of the telephone
line (picks up the receiver).
on-hook Your equipment releases (hangs up) the
telephone line.
online state The state the modem is in when data is
being exchanged with another computer over the telephone
line. Compare with terminal mode.
P
parity A method of detecting errors in data transmission.
Due to higher-quality telephone lines and higher-level error
control protocols, many host computers don’t support
parity.
parity bit A check bit appended to an array of binary digits
to make the sum of all the binary digits, including the check
bit, always odd or always even.
parity error Absence of the correct parity bit in a received
character.
PBX Private Branch Exchange. An automatic switchboard
for handling large concentrations of telephones (usually
digital extensions).
77 Glossary