Cisco 7925G Administration Guide

Usage notesPurposeNetwork protocol
When security is implemented, Cisco
Unified Wireless IP Phones use the TLS
protocol when securely registering with Cisco
Unified Communications Manager.
TLS is a standard protocol for securing
and authenticating communications.
Transport Layer
Security (TLS)
Cisco Unified Wireless IP Phones receive
and process UDP messages. RTP voice traffic
runs over UDP.
Connectionless messaging protocol
for delivery of data packets.
User Datagram
Protocol (UDP)
Related Topics
Phone Startup Process, on page 64
VoIP Wireless Network Components, on page 32
DHCP Settings, on page 121
Cisco Unified Wireless AP Interactions
Wireless IP phones use the same APs as wireless data devices. However, voice traffic over a WLAN requires
different equipment configurations and layouts than a WLAN that is used exclusively for data traffic. Data
transmission can tolerate a higher level of RF noise, packet loss, and channel contention than voice transmission.
Packet loss during voice transmission can cause choppy or broken audio and make the phone call inaudible.
Wireless IP Phones users are mobile and often roam across a campus or between floors in a building while
connected to a call. In contrast, data users remain in one place or occasionally move to another location. The
ability to roam while maintaining a call is one of the advantages of wireless voice, so RF coverage needs to
include stairwells, elevators, quiet corners outside conference rooms, passageways and so on.
To ensure good voice quality and optimal RF signal coverage, you must perform a site survey. The site survey
determines the AP platform and antenna type, AP placement, channel assignments and transmit power levels
that are required for the deployment.
After you deploy and use wireless voice, you should continue to perform postinstallation site surveys. When
you add a group of new users, install more equipment, or stack large amounts of inventory, you are changing
the wireless environment. A postinstallation survey verifies that the AP coverage remains adequate for optimal
voice communications.
Related Topics
Site Survey Verification, on page 44
AP Association
At startup, the Cisco Unified Wireless IP Phone scans for APs with SSIDs and encryption types that it
recognizes. The phone builds and maintains a list of eligible APs and uses the following variables to determine
the best AP.
Cisco Unified Wireless IP Phone 7925G, 7925G-EX, and 7926G Administration Guide
34
VoIP Wireless Network
Cisco Unified Wireless AP Interactions

Cisco 7925G Specifications

General

Keypad number of keys	12
Display diagonal	2 \
Display resolution	176 x 220 pixels
Call waiting	Yes
Lines quantity	6 lines
Voice codecs	G.711a, G.722, G.729a, iLBC
Security algorithms	128-bit WEP, SSL/TLS, WPA
Supported network protocols	DHCP, TFTP, DNS, SCCP, SRST
Input voltage	100 - 240 V
Dimensions (WxDxH)	52 x 20 x 127 mm
Minimum system requirements	Cisco Unified Communications Manager 4.1, 4.2, 4.3, 5.1, 6.0, 6.1, 7.0 + Cisco Unified Communications Manager Express 4.3 +
Input frequency	50/60 Hz
Storage temperature (T-T)	-30 - 60 °C
Operating temperature (T-T)	0 - 40 °C
Operating relative humidity (H-H)	10 - 95 %
Product type	IP Phone
Product color	Gray
Safety	UL 60950, CSA 22.2 No.60950, EN 60950, IEC 60950, AS/NZS 60950, IEC 60529 (IP 54)
Certification	47 CFR 15 B ICES-003 B EN 55022 B AS/NZS CISPR 22 B CISPR 22 B VCCI B EN 61000-3-2 EN 61000-3-3 KN 22 EN 55024 EN 50082-1 EN 61000-6-1 EN 300386 EN 60601-1-2 KN
Compliance industry standards	IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.1X, IEEE 802.11e

Weight and Dimensions

Weight	138 g