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SoundStation2W™ Security,
RF Co-Existence and Power Management
Application Note
Voice Communications
Division
December 2004
Polycom
®
designed the SoundStation2W™ to meet your needs for easy and reliable deployment.
This document outlines three key drivers for a worry free wireless solution.
Security on SoundStation2W:
SoundStation2W has proven and reliable security features in several areas: 1) 128-bit
authentication key for pairing the base station and console; 2) 64-bit voice encryption and DSS
frequency hopping on every voice call; 3) The AUX AUDIO feature is controlled from the console
rather than the base station (this feature allows external devices, such as a speaker, to be attached
to the SoundStation2W base station).
Pairing and Authentication
Every SoundStation2W has its base station and console pre-registered (paired) in the factory with a
unique 128-bit authentication key. When a system is installed the authentication key is verified,
and the base and console “lock” together and are synchronized. This prevents more than one
console from working with a single base station. This means that someone cannot use another
SoundStation2W console to intercept and listen in on a given phone call. The authentication key
between the base and console is verified every time the console goes off hook.
64-bit Voice Encryption
Once a call is established, voice packets traveling between the base station and console are
continuously encrypted using the DECT Standard Cipher (DSC) encryption algorithm. This
encryption algorithm was developed under the ETSI standardization body. Every time a call is
established a new 64-bit cipher key is generated during the authentication process. There are
300,000,000,000,000,000 possible keys. Voice packets coming from the base station are encrypted
and once the console receives them, the unique cipher key allows the console to decrypt the
packets. When voice packets are traveling from the console to the base station the process is
reversed. No encryption is present at the external telephone line connection. 64-bit encryption
exists solely between the SoundStation2W base station and console.
DSS Frequency Hopping Implementation
The SoundStation2W operates in the 2.4 GHz ISM frequency band (2.401 – 2.483 GHz). There are
95 channels in this band (863 KHz slots). Voice signals are digitized (packetized) and transmitted
over these 95 radio channels using a spread spectrum technique called frequency hopping. This
technique was originally developed for secure military communications. During this frequency
hopping, the radio hops 95 channels 100 times per second (every 10 ms) in pseudo-random
sequence. Voice packets will be dynamically allocated to the best 75 quality channels. Frequency
hopping coupled with digitized voice and dynamic channel allocation provides SoundStation2W
users with unprecedented reliability and quality. Plus, it makes it all the more difficult for someone
to intercept and listen in on a conference call taking place over a SoundStation2W.
AUX AUDIO on SoundStation2W
An auxiliary audio jack exists on the SoundStation2W base station that allows users to plug in
external equipment such as a recording device. However, since it is possible that the base station
could be located in a different room from the console, activation of the AUX AUDIO feature can
only be done from the console. The AUX AUDIO setting on the console is automatically set to OFF.
This setting must be changed to ON each time the feature is to be used in a call. If the AUX AUDIO
setting is switched to ON to allow an external device to be attached, the setting will automatically
default back to OFF once that call is ended.
Co-Existence with Other Wireless Equipment:
SoundStation2W is able to operate in the same environment with other wireless technologies with
little or no performance issues.
Co-existence with 802.11 (WLAN)
802.11 refers to a family of specifications developed for Wireless LAN technology. There are
several specifications in the 802.11 family:
• 802.11a – 5.8 GHz frequency band – no co-existence issues
• 802.11g – 2.4 GHz frequency band – no co-existence issues
• 802.11b – 2.4 GHz frequency band – generally no co-existence issues
While no co-existence issues exist between SoundStation2W and 802.11a & g devices, in rare
cases there can be some minor co-existence issues between SoundStation2W and 802.11b
devices. If the SoundStation2W base station is located less than 12 inches from an 802.11b
device, the 802.11b device may experience < 20% data rate reduction. Please note that this data
loss is below the normal throughput variation for any 802.11b connection in a typical office
environment. In very rare cases, a high 802.11b signal in the immediate vicinity of the
SoundStation2W may cause an occasional click in the 2W audio stream (most noticeable in dial
tone). The best practice is to keep the 2W base station > 6 feet away from any 802.11b device, and
keep the console > 3 feet from any 802.11b device. To maximize the 2W performance, try to keep
the base station close to the area where the console will be used most.
Co-existence with Bluetooth (WPAN)
Bluetooth WPAN (Wireless Personal Area Network) is a frequency hopping system that operates in
the 2.4 GHz frequency band. Used primarily for cellular phones, wireless headsets, PCs, printers,
and PDAs. Bluetooth has roughly a 30 ft. range. There are two classes of radio power within
Bluetooth – Class 1 (high power) and Class 2/3 (lower power). Generally there are no interference
issues between Bluetooth devices and SoundStation2W. Bluetooth will have no impact on
SoundStation2W voice quality. In the worst case, a Bluetooth Class 1 product will experience less
than 12% data rate reduction within 5 feet of SoundStation2W components. However, please note
that this data rate impact is less than the normal throughput variation for Bluetooth devices in a
typical office environment.
SoundStation2W Power Management:
There are three key principles to providing exceptional power management in wireless
communication devices: 1) Minimize the need to recharge to no more than once per week; 2)
Provide useful alerts and information regarding the power condition; 3) Make it easy and fast to
recharge in any usage environment.
The primary components of the SoundStation2W’s power management design are long talk time Li-
Ion battery pack (12 or 24 hour options), long standby time (80 or 160 hour options), persistent icon
on the LCD showing remaining talk time, low battery audible and visual alerts (when battery
reaches < 30% charge and/or < 60 minutes talk time), laptop-style portable charging design (re-
charge while you talk), and rapid charging cycles (< 4 hours or < 8 hours).
Additional Power Details:
- Battery packs contain 1900 mA Li-Ion cells (2 or 4 cells)
- Battery reaches rated talk time after 3 - 4 conditioning cycles
- Battery pack should be replaced every 9 - 12 months
- Battery pack contains overcharge protection and life extender mechanism
- Standby mode on the console conserves power
- EX mics are low-power consumption
- Talk time is rated with EX mics
Copyright © 2004 Polycom, Inc.
Polycom and the Polycom logo are registered trademarks and SoundStation2W is a trademark of Polycom, Inc. in the USA and various countries. All
other brand names, product names and trademarks are the sole property of their respective owners. Rev 12/04
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