Safety and Performance Information
Your access to emergency service through the phone requires that the phone receive power. If a power interruption occurs, service or emergency calling service dialing does not function until power is restored. If a power failure or disruption occurs, you may need to reset or reconfigure the equipment before you can use service or emergency calling service dialing.
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.
In European Union countries, use only external speakers, microphones, and headsets that are fully compliant with the EMC Directive [89/336/EC].
Ways to Provide Power to Your Phone
You can provide power to your phone in one of these ways:
Use the power adapter that comes with your phone.
If your network supports Power over Ethernet (PoE), you can plug your phone into the network. Plug an Ethernet cable into the Ethernet phone port and into the network.
If you are not sure whether your network supports PoE, check with your administrator.
Phone Behavior During Times of Network Congestion
Anything that degrades network performance can affect phone audio 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.
The LAN/Ethernet cable or other cables attached to the device should not be extended outside of the building.
The following phones have EnergyStar certification:
Cisco IP Phone 7811
Cisco IP Phone 7841
Any phone model that isn't listed in the above list isn't certified.
The product label is located on the bottom of the device.