Specifications

2-5
Cisco Unified Wireless IP Phone 7921G Administration Guide for Cisco Unified CallManager Release 4.1, 4.2, 5.0
OL-10802-02
Chapter 2 An Overview of the Voice Over IP Wireless Network
Understanding the Wireless LAN
Access points transmit and receive RF signals over channels within the 2.4 GHz
or 5.1 to 5.8 GHz frequency band. Regulatory domains determine the number of
channels that wireless communications can use within the frequency band.
Table 2-2 lists the frequency ranges and operating channels for three regulatory
domains. The Cisco Unified Wireless IP Phone 7921G has a fourth domain type
(product number is CP-7921G-W) for all other regions in the world. Wireless
LANs in the rest of the world will use 802.11d to inform the phone which
channels and data rates to use.
An access point broadcasts on a specific channel within the available channel
range. To provide a stable wireless environment and reduce channel interference,
you must specify non-overlapping channels for each access point. The
recommended channels for 802.11b/g in North America are channels 1, 6, and 11.
Note In a non controller-based wireless network, it is recommended that you statically
configure channels for each access point. If your wireless network uses a
controller, you can use the Auto-RF feature with minimal voice disruption.
Ta b l e 2-2 Regulatory Domain Frequency Band and Channel Usage
Regulatory Domain Frequency Band Range Operating Channels
Federal Communications
Commission (FCC)
Product number is CP-7921G-A
2.412-2.462 GHz 11 channels
5.15-5.25 GHz (UNII-1)
5.25-5.35 GHz (UNII-2)
5.725-5.825 (UNII-3)
5.470 - 5.725 (DFS)
12 channels
5.47-5.725 GHz (pending
approval
11 channels
ETSI (Europe)
Product number is CP-7921G-E
2.412-2.472 GHz 13 channels (1-13)
5.15-5.725 GHz 19 channels