Operation Manual

Appendix B Safety Notices
B-2
Cisco IP Phone 7960G and 7940G User Guide
OL-4637-01
Warning Do not work on the system or connect or disconnect cables during periods of
lightning activity.
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.
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.
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.