Contec FX-DS110-APE, User Manual, Page: 129 / 132

Appendix
FX-DS110-APE
118
DS (Direct Sequence)
A type of spectrum diffusion signal using narrow band modulation
with phase modulation, in which the diffusion is by means of phase
modulation using a broad band diffusion signal (pseudo random
strings).
CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance)
CSMA is a method of avoiding collision by which wireless
terminals listen before transmitting and do not transmit if they can
year transmissions from other wireless terminals. CSMA/CA is
CSMA plus additional collision avoidance functions.
Hidden Terminal Problem
When wireless terminals are farther apart then their electric signals
can reach, or their signals are obstructed by objects, neither may be
able to receive the other's signals. Any two such wireless
terminals are said to be hidden from each other. In Ad Hoc mode,
because the carrier sense function is not effective between hidden
terminals there is a higher probability of collisions and throughput
(the volume of information sent in a given time interval) is reduced.
RTS (Request to Send)
In communication via AP, transmission is controlled by CSMA/CA
plus RTS. In RTS, a wireless terminal asks the AP if it is all right
to transmit, and only transmits after an OK-to-send
acknowledgement signal is returned. This serves to avoid
unnecessary collisions when hidden terminals exist because hidden
terminals cannot transmit.
Roaming
This term has the same meaning as roaming for a portable phone or
PHS. The AP is in the role commonly called the 'antenna/base
station' for the phone or PHS, and the user unit is in the role of the
phone itself.
Peer-To-Peer
A network in which two or more nodes can communicate directly
with each other without going through another device.