Specifications

Glossary
Glossary-2
broadcast message
A data message that is transmitted by a wired or wireless device to all devices within a
network. Broadcast messages are forwarded across the AP.
broadcast storm
An occurrence where a large number of broadcast messages are sent through the network,
usually degrading network performance.
cell
A single AP and its wireless clients within a wireless infrastructure network containing
multiple APs.
channel (frequency)
The center radio frequency that the wireless device uses to transmit.
The RoamAbout PC Card can support up to 14 radio frequency channels as defined in the
IEEE 802.11 standard. The number of available channels for your PC Card is subject to radio
regulations that apply in your country. In most countries, these radio regulations adhere to
either the FCC or ETSI Standards. The North American (FCC) RoamAbout solution uses 11
channels.
CSMA/CA
Carrier Sense Multiple Access/Collision Avoidance. A protocol used to avoid collisions and
lost data. A device only transmits when it senses that no other device is transmitting. Radio
transmissions cannot tolerate collisions.
directional antenna
An antenna that radiates RF signals in a specific direction. A directional antenna typically has
a higher gain and can cover a greater distance than an omni-directional antenna. A 14 dBi
Yagi directional antenna is available as an option for the RoamAbout AP.
DSSS
Direct Sequence Spread Spectrum multiplies the data bits by a very fast pseudo-random bit
pattern that "spreads" the data into a large coded stream. This data stream takes the full
bandwidth of the channel. Because of the technology used in 802.11b, only DS solutions, as
opposed to Frequency Hopping (FH) solutions, can operate at 11 Mbps.
encryption
The transformation of data, for the purpose of privacy, into an unreadable format until
reformatted with a decryption key.