Radio Frequency Ranges - Cisco 7925G Administration Manual

VoIP Wireless Network
802.11a
802.11b
802.11d
802.11e
802.11g
802.11h
802.11i

Radio Frequency Ranges

WLAN communications use the following RF ranges:
2.4 GHz
5 GHz
Uses the 5 GHz band that provides more channels and improved data rates by using Orthogonal
Frequency Division Multiplexing (OFDM) technology. Dynamic Frequency Selection (DFS) and
Transmit Power Control (TPC) supports this standard.
Specifies the radio frequency (RF) of 2.4 GHz for both transmitting and receiving data at lower data
rates (1, 2, 5.5, 11 Mbps). Commonly called the Wi-Fi standard.
Enables APs to communicate available radio channels and acceptable power levels. The Cisco Unified
Wireless IP Phone always gives precedence to 802.11d to determine which channels and powers to
use. If the information is unavailable, then the phone reverts to the locally configured regulatory domain.
Supports Quality of Service (QoS).
Uses the same unlicensed 2.4 GHz band as 802.11b, but extends the data rates to provide greater
performance by using OFDM technology. OFDM is a physical-layer encoding technology for transmitting
signals using RF.
Supports the 5 GHz spectrum and transmit power management.
Specifies security standards.
Does not require licensing. To reduce interference within this bandwidth, WLANs transmit on
non-overlapping channels, which are typically limited to three channels, although Japan uses four
channels.
Many devices operate in the 2.4 GHz bandwidth, including cordless phones and microwave ovens, and
these devices can interfere with wireless communications. Interference does not destroy the signal, but
can reduce the transmission speed from 11 Mbps to 1 Mbps. RF interference can affect voice quality
over the wireless network.
Divided into several sections called Unlicensed National Information Infrastructure (UNII) bands and
each section has four channels. The channels are spaced at 20 MHz to provide non-overlapping channels
and more channels than 802.11b or 802.11g.
Cisco Unified Wireless IP Phone 7925G, 7925G-EX, and 7926G Administration Guide
Radio Frequency Ranges
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