Cisco 8800 Series Administration Manual page 38

External Devices
You can resolve these issues by isolating the voice traffic onto a separate VLAN. The switch port to which
the phone connects would be configured for separate VLANs for carrying:
• Voice traffic to and from the IP phone (auxiliary VLAN on the Cisco Catalyst 6000 series, for example)
• Data traffic to and from the PC that connects to the switch through the computer (access) port of the IP
Isolating the phones on a separate, auxiliary VLAN increases the quality of the voice traffic and allows a large
number of phones to be added to an existing network that does not have enough IP addresses for each phone.
For more information, see the documentation that is included with a Cisco switch. You can also access switch
information at this URL:
http://cisco.com/en/US/products/hw/switches/index.html
External Devices
We recommend that you use good-quality external devices that are shielded against unwanted radio frequency
(RF) and audio frequency (AF) signals. External devices include headsets, cables, and connectors.
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, we recommend that you take one or more
of these 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 external devices, cables, and connectors.
Caution
In European Union countries, use only external speakers, microphones, and headsets that are fully compliant
with the EMC Directive [89/336/EC].
USB Port Information
The Cisco IP Phones 8851, 8861, and 8865 support a maximum of five devices that connect to each USB
port. Each device that connects to the phone is included in the maximum device count. For example, your
phone can support five USB devices on the side port and five more standard USB devices on the back port.
Many third-party USB products count as multiple USB devices; for example, a device containing a USB hub
and headset can count as two USB devices. For more information, see the USB device documentation.
Cisco IP Phone 8800 Series Multiplatform Phones Administration Guide
22
phone (native VLAN)
About the Cisco IP Phone