Although Cisco Systems performs limited internal testing of
third-party headsets for use with the Cisco Unified IP Phones, Cisco does not
certify or support products from headset (or handset) vendors.
Cisco recommends the use of good quality headsets that are screened against unwanted radio frequency (RF) and
audio frequency (AF) signals. Depending on the quality of the headsets 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.
In some cases, hum may be reduced or eliminated by using a local power
cube or power 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 on a large scale.