Revision: C
CA12CD Product Summary.doc
11 of 12 pages
5.1
Frequency Hopping
The CA12CD avoids two users sharing the same channel and
timeslot under normal circumstances because it chooses the best
available channel, and will change channels if the channel in use
experiences interference from another user. In the event of
operation in a high-density installation where no better channel
and timeslot is available, two users near each other and sharing the
same channel and timeslot will experience occasional mutes of the
receive or transmit audio and occasional audio distortion artifacts,
rather than intercepted audio.
The CA12CD uses fixed-rate adaptive frequency hopping during
the idle-locked state, which is when the base and the remote are in
range but audio is not enabled. This was done to ensure that the
base and the remote are compensating for changes in the radio
signal spectrum due to other users and the presence of interferers,
and thus to improve the reliability of the link, but it has the effect of
adding a layer of security. The hop sequence is random, on the
basis of the physical environment.
The CA12CD uses aperiodic adaptive frequency hopping when the
audio link is enabled. The system is aperiodic because in this mode,
rather than changing channels at a fixed interval of time, the system
hops channels whenever there is another user sharing the same
channel and producing interference. In an environment with many
users, this adds a layer of security because users change channels
from time-to-time, rather than staying in a fixed channel. This
adaptive approach offers improved security relative to other
systems which use a single, common and fixed hop sequence.
5.2
Encryption
The protection against deliberate eavesdropping is through user
authentication and 64-bit true digital encryption of voice data
according to the standard algorithm of EN 300 175-7. A description
of the public portion of this encryption algorithm is available
through the website of the European Telecommunications
Standards Institute (ETSI) at www.etsi.org. Individuals and
organizations having a credentialed need for more detail regarding
the encryption scheme should contact Plantronics Engineering
through the Technical Assistance Center. The CA12CD in particular
and the DECT standard in general are considered secure-enough
for commercial applications requiring voice privacy. This assurance
is based on the 64-bit digital encryption of speech and the
internationally-recognized and standardized encryption algorithm
used.