User's Manual

Depending on the quality of these devices and their proximity to other devices such as mobile phones or
two-way radios, some audio noise may still occur. In these cases, Cisco recommends that you take one or
more of the following actions:
•
Move the external device away from the source of the RF or AF signals.
•
Route the external device cables away from the source of the RF or AF signals.
•
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 the system because Cisco has no control over the quality of external
devices, cables, and connectors. The system will perform adequately when suitable devices are attached using
good quality cables and connectors.
In European Union countries, use only external headsets that are fully compliant with the EMC Directive
[89/336/EC].
Caution
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
SAR
This product's SAR value meets applicable national SAR limits
of 1.6W/kg. The specific values can be found in the product
datasheet.
When carrying the product or using it while worn on your body,
either use an approved accessory such as a holster or otherwise
maintain a distance of 5 cm from the body to ensure compliance
with RF exposure requirements. Note that the product may be
transmitting even if you are not making a phone call.
Cisco Wireless IP Phone 8821 and 8821EX User Guide
89
Product Safety and Security
Phone Behavior During Times of Network Congestion