User`s guide

Aironet Wireless Communications, Inc. 1-1 Confidential and Proprietary
1
INTRODUCTION A
Welcome to the PC4500/4800
The PC4500 and the PC4800 are radio modules (typically used to create indoor wireless networks and
limited distance outdoor applications) that provide transparent wireless data communications between a
fixed, portable or mobile device and other wireless devices (such as access points connected to a wired
network infrastructure). Host devices can be any device equipped with a PC Card Type II or Type III
slot mechanical form factor. The host interface can be installed to operate as either a PC Card device, as
a serial communications (UART) device, or as an ISA device.
When used in standard network applications, the PC4500/4800 is a direct replacement for a wired
network interface card (NIC). The PC4500/4800 is fully Plug-and-Play compatible when used in host
devices which support the technology.
The PC4500/4800 uses the 2.4GHz direct sequence spread spectrum technology as defined by the IEEE
802.11 Wireless LAN specification in order to accomplish real-time communication between a host
computer or other device on a radio-based local area network. Direct sequence modulation provides
secure, interference-immune communication and does not require a license for operation. The
PC4500/4800 comes standard with Aironet enhancements to the 802.11 protocol which can be enabled to
allow system optimizations which improve throughput and allow for more robust and reliable roaming.
The PC4500 is capable of transmitting and receiving at data rates of 1 and 2 Mbit/s, and the PC4800 can
transmit and receive at data rates of 1, 2, 5.5, and 11 Mbit/s. The adapter can be configured to use either
rate alone or automatically switch between both rates in order to maintain maximum throughput at a
given range. Another advanced feature of the PC4500/4800 is the use of antenna diversity to offer
improved data delivery (higher throughput) as well as extending the usable communication range of the
PC4500/4800. Two antenna connectors are available which allows the connection of two antennas at the
same time. These antennas can be configured as a single unit diversity antenna or two separate remote
antennas. Connecting two antennas (or using the diversity antennas supplied by Aironet) allows the
PC4500/4800 to detect and use the strongest signal coming from either of the antennas to improve
receiver performance. The PC4500/4800 can be configured to use a single antenna for all transmissions
or to choose the antenna offering the best data delivery. In this way, the PC4500/4800 provides you with
the best communication range and reliability for your environment.
In addition to the secure and highly reliable data communication provided by direct sequence spread
spectrum technology, the PC4500/4800 also offers a data encryption option. The encryption method is
referred to as wired equivalent privacy (WEP) and is defined as an optional feature in the 802.11