Polycom SoundStation 2W Application Note

Brand: Polycom

Model: SoundStation 2W

Type: Application Note

Polycom SoundStation 2W is a wireless conferencing solution that offers secure and reliable communication for your business. With its 128-bit authentication key, 64-bit voice encryption, and DSS frequency hopping, you can be confident that your conversations will remain private. The device also features an auxiliary audio jack that allows you to connect external devices, such as a recording device, for added flexibility. Additionally, the SoundStation 2W is designed to coexist with other wireless technologies, such as 802.11 and Bluetooth, with minimal interference.

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

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

Polycom SoundStation 2W Application Note

Polycom SoundStation 2W Application Note

Polycom SoundStation 2W Application Note

Related papers

Other documents