•
Use shielded cables for the external device, or use cables with a better shield and connector.
•
Shorten the length of the external device cable.
•
Apply ferrites or other such devices on the cables for the external device.
Cisco cannot guarantee the performance of external devices, cables, and connectors.
In European Union countries, use only external speakers, microphones, and headsets that are fully compliant
with the EMC Directive [89/336/EC].
Caution
Bluetooth Wireless Headset Performance
The Cisco IP Phones support Bluetooth Class 2 technology when the headsets support Bluetooth. Bluetooth
enables low-bandwidth wireless connections within a range of 30 feet (10 meters). The best performance is
in the 3- to 6-foot (1- to 2-meter) range. You can connect up to five headsets, but only the last one connected
is used as the default.
Because there can be potential interference issues, Cisco recommends that you move 802.11b/g devices,
Bluetooth devices, microwave ovens, and large metal objects away from the wireless headset.
For a Bluetooth wireless headset to work, it does not need to be within direct line-of-sight of the phone, but
some barriers, such as walls or doors, and interference from other electronic devices, can affect the connection.
Power Information
Connect your Cisco IP phone to your LAN using a CAT 5e Ethernet cable to enable full functionality of your
Cisco IP phone. If your Ethernet port is equipped with Power over Ethernet (PoE), your Cisco IP phone can
be powered through the LAN port. Do not extend the LAN Ethernet cable outside the building.
Phone Behavior During Times of Network Congestion
Anything that degrades network performance can affect Cisco IP Phone voice and video quality, and in some
cases, can cause a call to drop. Sources of network degradation can include, but are not limited to, the following
activities:
•
Administrative tasks, such as an internal port scan or security scan
•
Attacks that occur on your network, such as a Denial of Service attack
To reduce or eliminate any adverse effects to the phones, schedule administrative network tasks during a time
when the phones are not being used or exclude the phones from testing.
FCC Compliance Statements
The Federal Communications Commission requires compliance statements for the following:
Cisco IP Phone 8811, 8841, 8851, 8851NR, and 8861 User Guide for Cisco Unified Communications Manager
10.5
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Product Safety and Security
Bluetooth Wireless Headset Performance