Sierra Wireless DART 200, Руководство пользователя

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DART 200 CDPD Modem User’s Guide Glossary
Sierra Wireless, Inc. Glossary-10
full duplex
Communications operation where simultaneous two-way
data transmission occurs across the data link. Devices
using this method can send and receive at the same time.
half duplex
Communications operation where data transmission
occurs in either direction but not at the same time.
Devices using this method can’t receive while sending or
vice versa.
handshaking
Another term for flow control.
parity A simple method of detecting if the character just
received over the link is what was transmitted. A single
bit is added to the binary string of bits representing the
character to be transmitted. This bit is set to make the
total number of binary ones in the character string plus
the parity bit equal to an even or an odd number. There
are three types of parity: (E)ven, (O)dd, or (N)one.
port
A standard piece of the Internet Protocol address
structure. The port serves as an extension of the IP
Address to permit a single host (one IP Address) to
provide multiple servers (applications) each defined by its
unique port number.
power
product
A carrier configurable MDBS parameter defining the
desired relationship between received and transmitted
signal strength.
Restart
To turn off and then turn on a computer.
roaming
Used to describe the situation where a user from carrier A
is operating in the service area of carrier B.
Status
Registers or
S-Registers
RAM locations inside the modem that hold information
about certain functions that the modem performs. An
example is S9 (the ninth S-Register) that holds the
information on how long to wait for the modem tone
(carrier) to show up before hanging up.
stack
Refers to the TCP protocol stack, so-called because it is
composed of a number of protocol layers (physical, data
link, network, transport, and so on). Required to operate
with Internet Protocol. Can be implemented in software
(PC), or hardware (DART firmware). Trumpet is a
software stack.
start bit
The bit preceding each asynchronous character. Signals
the receiving modem that a new character is starting.
There is always 1 start bit.
stop bit
There is at least 1 stop bit at the end of each character to
be transmitted (sometimes two). One is typical. Resets the
modem chip in preparation for receiving the next
character.