Introduction
Documentation Number: LWS40xA-906m
Chapter 1
5
Black Box Corporation - 1001 Park Drive - Lawrence, PA 15055-1018
www.blackbox.com
-- Tech Support and Ordering: 724-746-5500 - Fax: 724-746-0746
IEEE 802.11g
IEEE 802.11g standard specifies a WLAN that operates on the 2.4 GHz band
at data rates up to 54 Mbps, but is backward compatible with the earlier
802.11b standard (which operates at up to 11 Mbps). Systems can
incorporate 802.11b and 802.11g equipment and they will interoperate.
However, when connected into the same network the 802.11g equipment will
operate at the 11 Mbps limitation of the 802.11b equipment.
For media access, 802.11 wireless networks use CSMA/CA, a scheme in
which a station that intends to transmit ‘listens’ for traffic on the radio carrier
frequency and sends data packets if the frequency is clear. If the receiving
station receives the packet intact it sends an acknowledgement (ACK) to
confirm the packet has been received. If the transmitting station does not
receive an ACK it assumes a collision occurred and transmits again after a
random delay period.
Communications distances vary depending on the type and thickness of
material around an 802.11g node. The transmitter power output, the type of
antenna used and the amount of attenuation through materials also affects the
useable range. Electromagnetic noise, reflections, the amount of network
traffic, other radio devices operating in the same frequency band also affect
range and overall performance. In an infrastructure network the number of
access points and their coverage pattern also affect how well the system
operates. Typically an 802.11 device operating indoors will have a range
from 100 feet minimum to about 300 feet maximum. Outdoors, some
products, using high gain antennae may achieve line-of-sight ranges of five
miles or more.
Security is a significant concern for WLAN users. Whether security threats
originate intentionally or unintentionally, wireless systems are more
susceptible than wired systems. LWS40xA offer several security options
including WEP (Wired Equivalent Privacy), LEAP (Lightweight Extensible
Authentication Protocol) and others.
Introduction
6
Chapter 1
Documentation Number: LWS40xA-906m
Black Box Corporation - 1001 Park Drive - Lawrence, PA 15055-1018
www.blackbox.com
-- Tech Support and Ordering: 724-746-5500 - Fax: 724-746-0746
LWS40xA Startup Procedure
Setup and configuration of your LWS40xA wireless serial server is fast,
straightforward and simple. You have several options from which to choose. The
following procedure outlines an easy way to get your server set up and operational.
1. Package Checklist
To begin, check to see that you have everything you will require. The
contents of your LWS40xA package should include:
•
One LWS401A, LWS406A, LWS402A or LWS404A Wireless Serial
Server
•
One SMA antenna
•
One Operation Manual
•
One Quick Start Guide
•
One CD containing
o
Device Detection software
o
Serial-IP Virtual COM Port Software
o
the Operation Manual (in pdf format)
o
the Quick Start Guide (in pdf format)
2. Hardware Setup
1.
Connect the antenna to your LWS40xA
2.
Connect a standard Ethernet (CAT5/RJ-45 straight through) cable
from the PC network adapter to the LWS40xA Configuration Port
3.
Connect 24 VAC or 12 to 30 VDC power to the LWS40xA
4.
Connect the serial port on the LWS40xA to the serial port on your
serial device. This is optional during the initial configuration steps
but will be required for operation.
For RS-232 operation, your LWS40xA is configured as a DTE and uses a DB-
9M connector. Use a straight through RS-232 cable if your serial device is
configured as a DCE. If your serial device is configured as a DTE you will have
to use a null modem (crossover) cable.