ProSoft Technology inRA-x ILX34-AENWG, Руководство по установке

Страница: 68 / 79

ILX34-AENWG ♦ POINT I/O Platform Glossary of Terms
Wireless Point I/O Adapter Setup Guide
Page 68 of 79
ProSoft Technology, Inc.
July 31, 2009
The host name can also refer to the fully qualified domain name (FQDN), or in
this example, www.trading.com. Both naming methods seem to be used
interchangeably in various documents. For the purposes of this document, the
host name will refer to the FQDN, or as in this example, www.trading.com.
Hub
A central connecting device that joins devices together in a star configuration.
Hubs are generally not suitable for use in I/O control systems, since they are
time-critical applications that cannot tolerate lost packets.
Hz
Hertz. The international unit for measuring frequency equivalent to the older unit
of cycles per second. One megahertz (MHz) is one million hertz. One gigahertz
(GHz) is one billion hertz. The standard US electrical power frequency is 60 Hz.
802.11a devices operate in the 5 GHz band; 802.11b and g devices operate in
the 2.4 GHz band.
I
IEEE
Institute of Electrical and Electronics Engineers, Inc. IEEE is a professional
organization with members in over 175 countries and is an authority in technical
areas such as computer engineering and telecommunications. IEEE developed
the 802.11 specifications.
Implicit messaging
Real-time messaging of I/O data.
IP
Internet protocol that provides the routing mechanism for messages. All
messages contain not only the address of the destination station, but the address
of a destination network, which allows messages to be sent to multiple networks
within an organization or around the world.
IP Address
A 32-bit identification number for each node on an Internet Protocol network.
These addresses are represented as four sets of 8-bit numbers (numbers from 0
to 255), with decimals between them. Networks using the TCP/IP Protocol route
messages based on the IP address of the destination. Each number can be 0 to
255. For example, 192.168.0.100 could be an IP address. Each node on the
network must have a unique IP address.
K
Key
A set of information (often 40 to as much as 256 bits) that is used as a seed to an
encryption algorithm to encrypt (scramble) data. Ideally, the key must also be
known by the receiver to decrypt the data.