Cisco Unified IP Phone 7940G Specification Guide
3-5
Cisco IP Phone Administration Guide for Cisco CallManager 4.0, Cisco IP Phones 7960G/7940G
OL-4825-01
Chapter 3 Setting Up the Cisco IP Phone
Before You Begin
Warning
Do not work on the system or connect or disconnect cables during periods of
lightning activity.
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 both use RJ-45
connectors. Use caution when connecting cables.
to telephone network voltage (TNV) circuits. LAN ports contain SELV circuits,
and WAN ports contain TNV circuits. Some LAN and WAN ports both use RJ-45
connectors. Use caution when connecting cables.
The following warnings apply when you use an external power supply.
Warning
This product relies on the building's installation for short-circuit (overcurrent)
protection. Ensure that a fuse or circuit breaker no larger than 120 VAC, 15 A
U.S. (240 VAC, 10 A international) is used on the phase conductors (all
current-carrying conductors).
protection. Ensure that a fuse or circuit breaker no larger than 120 VAC, 15 A
U.S. (240 VAC, 10 A 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.
as the main disconnecting device.
Using External Devices with Your Cisco IP Phone
The following information applies when you use external devices with the
Cisco IP Phone.
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.
microphones, and headsets) that are screened against unwanted radio frequency
(RF) and audio frequency (AF) signals.