Cisco AIR-AP1252AG-A-K9 Hardware Installation Guide - Page 71

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Cisco Aironet 1250 Series Access Point Hardware Installation Guide

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Chapter 3

Troubleshooting 1250 Series Autonomous Access Points

Low Power Condition on Autonomous Access Points

Low Power Condition on Autonomous Access Points

The access point with two radio modules can be powered from the 1250 DC power module or from the

1250 in-line power injector. The access point supports the Cisco Intelligent Power Management.

With only one radio module installed, the access point (powered device) can be powered by an 802.3af

power source. It requires 15.4 W with 100 m of CAT 5E (or higher) Ethernet cable. When the access

point is being used in a PoE configuration, the power drawn from the power sourcing equipment (PSE),

such as a power injector, is higher by an amount dependent on the length of the interconnecting cable.

For full dual radio module operation, the access point requires 18.5 W with 100 m CAT 5E (or higher)

Ethernet cable.

Caution

Current switches, power patch pannels, and IEEE 802.3af compliant power sources are not able to

provide sufficient power to the access point with both radio modules installed.

Note

If your access point is connected to in-line power, do not connect the power module to the access point.

Using two power sources on the access point might cause the access point to shut down to protect internal

components and might cause the switch to shut down the port to which the access point is connected. If

your access point shuts down, you must remove all power and reconnect only a single power source.

On power up, the access point is placed into low power mode (both radios are disabled), Cisco IOS

software loads and runs, and power negotiation determines if sufficient power is available. If there is

sufficient power then the radios are turned on; otherwise, the access point remains in low power mode

with the radios disabled to prevent a possible over-current condition. In low power mode, the access

point activates the Status LED low power error indication, displays a low power message on the browser

and serial interfaces, and creates an event log entry (see the

“Checking the Autonomous Access Point

LEDs” section on page 3-2

and

“Inline Power Status Messages” section on page 3-8

).

Intelligent Power Management

To help avoid an over-current condition with low power sources and to optimize power usage on Cisco

switches, Cisco developed Intelligent Power Management, which uses Cisco Discovery Protocol (CDP)

to allow powered devices (such as your access point) to negotiate with a Cisco switch for sufficient

power.

The access point supports Intelligent Power Management and as a result of the power negotiations, the

access point will either enter full power mode or remain in low power mode with the radios disabled.

Note

Independent of the power negotiations, the access point hardware also uses the 802.3af classification

scheme to indicate the power required from the power source. However, the power source cannot report

the power available to the access point unless the power source also supports Intelligent Power

Management.

Some Cisco switches might require a software upgrade to support Intelligent Power Management. If the

software upgrade is not desired, you can configure the access point to operate in pre-standard

compatibility mode and the access point automatically enters full power mode (with a single radio

module installed) if these Cisco switches are detected in the received CDP ID field.

Section	Page
Cisco Aironet 1250 Series Access Point Hardware Installation Guide	1
Contents	3
Preface	9
Audience	9
Purpose	9
Organization	9
Conventions	10
Related Publications	12
Locating the Product Serial Number	13
Obtaining Documentation, Obtaining Support, and Security Guidelines	14
Overview	15
Product Terminology	15
Autonomous Access Points	15
Lightweight Access Points	16
Guidelines for Using Cisco Aironet Lightweight Access Points	16
Hardware Features	17
Radio Module Slots	19
Single or Dual-Radio Operation	19
Operating Modes	19
Spatial Multiplexing	19
Maximum Ratio Combining	20
Antennas Supported	20
LEDs	21
Ethernet Port	21
Console Port	22
Power Sources	22
UL 2043 Compliance	22
Anti-Theft Features	23
Network Examples with Autonomous Access Points	24
Root Unit on a Wired LAN	24
Repeater Unit that Extends Wireless Range	25
Central Unit in an All-Wireless Network	26
Workgroup Bridge Network	26
Network Example with Lightweight Access Points	27
Installing the Access Point	29
Safety Information	30
FCC Safety Compliance Statement	30
General Safety Guidelines	30
Warnings	30
Unpacking the Access Point	31
Package Contents	31
Basic Installation Guidelines	32
Before Beginning the Installation	32
Access Point Bottom Connector Access Openings	32
Installation Summary	33
Mounting Overview	33
Mounting on a Horizontal or Vertical Surface	35
Mounting Below a Suspended Ceiling	37
Mounting Above a Suspended Ceiling	39
Installing Option One	41
Installing Option Two	43
Installing Option Three	44
Mounting to a Network Cable Box	46
Mounting on a Desktop or Shelf	47
Connecting the Ethernet and Power Cables	48
Connecting to an Ethernet Network with an Inline Power Source	49
Connecting to an Ethernet Network with Local Power	50
Powering Up the Access Point	50
Installing or Removing the Mounting Plate Latch	51
Installing the Mounting Plate Latch	51
Removing the Mounting Plate Latch	51
Installing the Access Point to the Mounting Plate	52
Mounting Plate Not Attached to a Surface	52
Mounting Plate Attached to a Surface	54
Securing the Access Point	55
Securing the Access Point to the Mounting Plate	55
Using a Security Cable to Secure the Access Point	57
Removing the Access Point From the Mounting Plate	58
Removing a Radio Module	60
Inserting a Radio Module	62
Troubleshooting 1250 Series Autonomous Access Points	65
Checking the Autonomous Access Point LEDs	66
Checking the Power Injector LEDs	68
Checking Basic Settings	69
Default IP Address Behavior	69
Enabling the Radio Interfaces	69
SSID	70
WEP Keys	70
Security Settings	70
Low Power Condition on Autonomous Access Points	71
Intelligent Power Management	71
Inline Power Status Messages	72
Configuring Power Using the CLI	75
Issuing the Cisco IOS Command Using the CLI	77
Configuring the Access Point System Power Settings Using a Browser	77
Running the Carrier Busy Test	80
Running the Ping Test	81
Resetting to the Default Configuration	82
Using the MODE Button	82
Using the Web Browser Interface	83
Reloading the Access Point Image	83
Using the MODE Button	83
Web Browser Interface	84
Browser HTTP Interface	84
Browser TFTP Interface	85
Obtaining the Access Point Image File	86
Connecting to the Access Point Locally	86
Obtaining the TFTP Server Software	88
Troubleshooting 1250 Series Lightweight Access Points	89
Guidelines for Using Cisco Aironet Lightweight Access Points	90
Using DHCP Option 43	90
Checking the Lightweight Access Point LEDs	91
Checking the Power Injector LEDs	94
Low Power Condition for Lightweight Access Points	95
Intelligent Power Management	95
Inline Power Status Messages	96
Configuring Power Using Controller CLI Commands	99
Manually Configuring Controller Information Using the Access Point CLI	100
Configuring Controller Information	101
Clearing Manually Entered Controller Information	101
Manually Resetting the Access Point to Defaults	101
MODE Button Setting	101
Connecting to the Access Point Locally	102
Obtaining the TFTP Server Software	103
Translated Safety Warnings	105
Declarations of Conformity and Regulatory Information	107
Manufacturers Federal Communication Commission Declaration of Conformity Statement	108
VCCI Statement for Japan	109
Industry Canada	109
Canadian Compliance Statement	109
European Community, Switzerland, Norway, Iceland, and Liechtenstein	110
Declaration of Conformity with Regard to the R&TTE Directive 1999/5/EC	111
Declaration of Conformity for RF Exposure	113
Guidelines for Operating Cisco Aironet Access Points in Japan	114
Japanese Translation	114
English Translation	114
Administrative Rules for Cisco Aironet Access Points in Taiwan	115
Access Points with IEEE 802.11a Radios	115
Chinese Translation	115
English Translation	115
All Access Points	116
Chinese Translation	116
English Translation	116
Chinese Translation	117
English Translation	117
Operation of Cisco Aironet Access Points in Brazil	118
Access Point Models	118
Regulatory Information	118
Portuguese Translation	118
English Translation	118
Declaration of Conformity Statements	119
Declaration of Conformity Statements for European Union Countries	119
Access Point Specifications	121
Channels and Power Levels	125
Console Cable Pinouts	127
Overview	128
Console Port Signals and Pinouts	128
Configuring DHCP Option 43 for Lightweight Access Points	129
Overview	130
Configuring Option 43 for 1000 and 1500 Series Access Points	131
Configuring Option 43 for 1100, 1130, 1200, 1240, 1250, 1300, and 1520 Series Lightweight Access Points	132
Glossary	133

Cisco AIR-AP1252AG-A-K9 Hardware Installation Guide - Page 71

Low Power Condition on Autonomous Access Points, Intelligent Power Management

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