Cisco 7911G - IP Phone VoIP Phone Manual page 16

Cisco recommends the use of good quality external devices, for example, headsets that are screened
against unwanted radio frequency (RF) and audio frequency (AF) signals. Depending on the quality of
these devices and their proximity to other devices such as mobile phones and two-way radios, some
audio noise or echo may still occur. An audible hum or buzz may be heard by either the remote party
or by both the remote party and the Cisco Unified IP Phone user. Humming or buzzing sounds can be
caused by a range of outside sources: for example, electric lights, electric motors, or large PC monitors.
See Using External Devices, page 2
In some cases, hum may be reduced or eliminated by using a local power cube or power
Note
injector.
These environmental and hardware inconsistencies in the locations where Cisco Unified IP Phones are
deployed means that there is not a single headset solution that is optimal for all environments.
Cisco recommends that customers test headsets in their intended environment to determine
performance before making a purchasing decision and deploying en mass.
Audio Quality Subjective to the User
Beyond the physical, mechanical and technical performance, the audio portion of a headset must
sound good to the user and to the party on the far end. Sound quality is subjective and Cisco cannot
guarantee the performance of any headsets. However, a variety of headsets from leading headset
manufacturers have been reported to perform well with Cisco Unified IP Phones. See manufacturer's
sites for details.
8
for more information.
OL-15428-01