Cisco 8821 Guide

Cisco Wireless IP Phone 8821 and 8821-EX Wireless LAN Deployment Guide
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Delivery Traffic Indicator Message (DTIM)
The Cisco Wireless IP Phone 8821 and 8821-EX can use the DTIM period to schedule wakeup periods to check for broadcast
and multicast packets as well as any unicast packets.
If proxy ARP is enabled, then the Cisco Wireless IP Phone 8821 and 8821-EX do not have to wake up at DTIM.
For optimal battery life and performance, is recommended to set the DTIM period to 2 with a beacon period of 100 ms.
The DTIM period is a tradeoff between battery life and multicast performance.
Broadcast and multicast traffic will be queued until the DTIM period when there are power save enabled clients associated to
the access point, so DTIM will determine how quickly these packets can be delivered to the client. If using multicast
applications, a shorter DTIM period can be used.
When multiple multicast streams exist on the wireless LAN frequently, then it is recommended to set the DTIM period to 1.
Dynamic Transmit Power Control (DTPC)
To ensure packets are exchanged successfully between the Cisco Wireless IP Phone 8821 or 8821-EX and the access point,
Dynamic Transmit Power Control (DTPC) should be enabled.
DTPC prevents one-way audio when RF traffic is heard in one direction only.
If the access point does not support DTPC, then the Cisco Wireless IP Phone 8821 and 8821-EX will use the highest available
transmit power depending on the current channel and data rate.
The access point’s radio transmit power should not have a transmit power greater than what the Cisco Wireless IP Phone 8821
and 8821-EX can support.
Call Capacity
Design the network to accommodate the desired call capacity.
The Cisco Access Point can support up to 27 bi-directional voice streams for both 802.11a/n/ac and 802.11g/n at a data rate of
24 Mbps or higher. To achieve this capacity, there must be minimal wireless LAN background traffic and initial radio frequency
(RF) utilization.
The number of calls may vary depending on the data rate, initial channel utilization, and the environment.
Audio Only Calls
Below lists the maximum number of audio only calls (single bi-directional voice stream) supported per access point / channel.
Max # of
Streams
Audio Codec
Audio
Bit Rate
802.11 Mode
Data Rate
13
G.722 / G.711
64 Kbps
802.11a/n or 802.11g/n +
Bluetooth Disabled
6 Mbps
20
G.722 / G.711
64 Kbps
802.11a/n or 802.11g/n +
Bluetooth Disabled
12 Mbps
27
G.722 / G.711
64 Kbps
802.11a/n/ac or 802.11g/n
+ Bluetooth Disabled
24 Mbps or higher

Cisco 8821 Specifications

General

Wi-Fi	Yes
Ethernet LAN	No
Wi-Fi standards	802.11a, Wi-Fi 5 (802.11ac), 802.11b, 802.11g, Wi-Fi 4 (802.11n)
Bluetooth version	3.0+HS
Security algorithms	EAP-FAST, EAP-TLS, PEAP, WPA
Networking standards	IEEE 802.11a, IEEE 802.11ac, IEEE 802.11b, IEEE 802.11d, IEEE 802.11e, IEEE 802.11g, IEEE 802.11n, IEEE 802.11r
USB 2.0 ports quantity	1
Voice codecs	G.711, G.711a, G.722, G.729, G.729ab, iLBC
Volume control	Digital
Product type	IP mobile phone
Product color	Black
Input frequency	50 - 60 Hz
AC adapter input voltage	100 - 240 V
AC adapter output current	0.2 A
Display diagonal	2.4 \
Display resolution	240 x 320 pixels
Frequency band	2.412, 2.472, 5.180, 5.240, 5.260, 5.320, 5.500, 5.700, 5.745, 5.825 GHz
Lines quantity	- lines
Phonebook capacity	- entries
Storage temperature (T-T)	-30 - 60 °C
Operating temperature (T-T)	-10 - 50 °C
Operating relative humidity (H-H)	10 - 95 %
Safety	UL 60950-1, CAN/CSA 60950-1, EN 60950-1, IEC 60950-1, AS/NZS 60950.1, IEC 60529 (IP 67)
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 B ● EN 55024 ● EN 50082-1 ● EN 61000-6-1 ● EN61000-6-3 ● EN 300386 ● EN 60601-1-2 ● KN
Number of handles included	1 pc(s)
Harmonized System (HS) code	85171800

Weight and Dimensions

Depth	17 mm
Width	56 mm
Height	132 mm
Weight	126 g