Note
•
Unpowered hubs are not supported, and powered hubs with more than four ports are not supported.
•
USB headsets that connect to the phone through a USB hub are not supported.
•
The Cisco Unified Video Camera that connects to the phone through a USB hub is not supported.
External Speakers and Microphone
External speakers and microphones are plug-and-play accessories. You can connect an external PC-type
microphone and powered speakers (with amplifier) on the Cisco Unified IP Phone 9951 or 9971 by using the
line in/out jacks. Connecting an external microphone disables the internal microphone and connecting an
external speaker disables the internal phone speaker.
Using poor quality external audio devices, playing loudspeakers at very loud volumes, or placing the
microphone very close to the loudspeaker may result in undesirable echo for other parties on your
speakerphone calls.
Note
Headsets
Although Cisco Systems performs internal testing of third-party headsets for use with Cisco Unified IP Phones,
Cisco does not certify nor support products from headset or handset vendors.
The phone reduces some background noise that a headset microphone detects, but if you want to further reduce
the background noise and improve the overall audio quality, use a noise cancelling headset.
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 headsets and
their proximity to other devices, such as mobile (cell) phones and two-way radios, some audio noise or echo
may still occur. Either the remote party or both the remote party and the Cisco Unified IP Phone user may
hear an audible hum or buzz. A range of outside sources can cause humming or buzzing sounds; for example,
electric lights, electric motors, or large PC monitors.
In some cases, using a local power cube or power injector may reduce or eliminate hum.
Note
These environmental and hardware inconsistencies in the locations where Cisco Unified IP Phones are deployed
mean that no single headset solution is optimal for all environments.
Cisco recommends that customers test headsets in the intended environment to determine performance before
making a purchasing decision and deploying on a large scale.
Related Topics
External device use, on page 65
Cisco Unified IP Phone 8961, 9951, and 9971 Administration Guide for Cisco Unified Communications Manager 10.0
(SIP)
59
Cisco Unified IP Phone Installation
External Speakers and Microphone
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