Multidrop Line
Single communications circuit interconnecting many stations (nodes) each containing terminal devices.
Multiplex
To interleave or simultaneously transmit two or more messages on a single channel.
N
NAK
Negative Acknowledgement. This control character indicates that the last block transmitted was in error and that the receiver is expecting a retransmission.
Node
A point of interconnection on a circuit.
Noise
Random electrical signals introduced by components of the circuit or natural disturbances which can produce errors in transmission.
Null Modem
See Modem Eliminator.
O
Odd Parity
Odd parity refers to the appending of a 0 or 1 value bit to the data bits of a character to ensure that an odd number of 1 value bits are sent. See also Even Parity and Parity.
Off line
Describes equipment and activities connected to, but not currently accessible by, a computer.
On line
Describes activities and equipment currently connected to an accessible by a computer.
P
PABX
Private Automatic Branch Exchange. An automatic switchboard for handling large concentrations of telephones (extensions).
Packet
Group of bits including data and control elements that are transmitted as a whole.
Page 276
