User Manual

14
Warning To avoid electric shock, do not connect safety extra low voltage (SELV) circuits to
telephone network voltage (TNV) circuits. LAN ports contain SELV circuits, and WAN
ports contain TNV circuits. Some LAN and WAN ports use RJ-45 connectors. Use caution
when connecting cables.
Using an External Power Supply
The following warnings apply when you use the external power supply with the Cisco IP Phone:
Warning This product relies on the building's installation for short-circuit (over current)
protection. Ensure that a fuse or circuit breaker no larger than 120 VAC, 15A U.S. (240 VAC,
10A international) is used on the phase conductors (all current-carrying conductors).
Warning The device is designed to work with TN power systems.
Warning The plug-socket combination must be accessible at all times because it serves as the
main disconnecting device.
Caution Use only a Cisco-approved power supply.
Using External Devices with Your Cisco IP Phone
The following information applies when you use external devices with the Cisco IP Phone:
Cisco recommends the use of good quality external devices (speakers, microphones, and 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
or two-way radios, some audio noise may still occur. In these cases, Cisco recommends that you take
one or more of the following 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 screened cables for the external device, or use cables with a better screen and connector.
• Shorten the length of the external device cable.