System information

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Appendix

Bluetooth and Wireless Fidelity

interference

Bluetooth is a wireless communication technology that is especially

appropriate for cable replacement, but is not a personal mobility

technology. The IP Phone 1140E and IP Phone 1150E are Class 3

Bluetooth devices. This means the Bluetooth works up to 10 meters.

However, audio performance in a Bluetooth headset suffers if you walk

away from the phone. After 10 meters, the link drops.

Both Bluetooth and Wireless Fidelity (WiFi) wireless protocols operate

in the 2.40 Industrial, Scientific and Medical (ISM) Radio Frequency

(RF) band. Bluetooth and WiFi wireless communications can interfere

with each other. Interference can occur between Bluetooth and WiFi

wireless communications, which results in lowered data throughput.

Bluetooth utilizes a frequency hopping mechanism so that it does not

stick in a fixed channel like WiFi does and the master and slave devices

keep hopping synchronously during whole connecting time. However,

occasionally Bluetooth devices can hop into a channel, which other WiFi

devices occupy and can encounter corrupted packet at that hop. The

Bluetooth headset (audio-oriented) devices are more susceptible to radio

interference than other data-oriented devices because Synchronous

Connection-Oriented Link (SCO) data do not re-transmit in the Bluetooth

protocol. When an audio packet is corrupted or lost, you can hear

crackling and popping noise due to the missing data. This is evident when

you listen to dial tones or other continuous audio tones. During regular

speech, this effect is less perceptible.

The Bluetooth and WiFi interference is a normal part of network operation.

If Bluetooth and WiFi must coexist, the following mitigation techniques can

produce a more satisfactory user experience when WiFi and Bluetooth

operate simultaneously.

• The IP Phone 1140E and IP Phone 1150E can transmit at up to 0

decibels (dBm). The IP Phone Bluetooth receivers can handle an

Nortel Communication Server 1000

IP Phones Fundamentals

NN43001-368 05.02 26 May 2009