Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

9971 KEM issue with CME

Hi,

I have an IP Telephny set up with CME running on version 9.1.We have an 8961 phone connected with 1 KEM .Actually we requied to connect 2 KEM for our recepetion and 8961 will support only 1 KEM .Thats why we purchased 9971 phone.

But when  connected 9971 with 2 KEM i got an error like " Your IP Phone do not have power to provide the accessory connected ".

From the following Power information showing that 9971 requires power adapter for connnecting 3 KEMS.

But it also mentoning that with POE it will work with 1 KEM.But I tried with 1 KEM but i am getting the same error.

Also mentioning with AT power it will support 2 KEMs....what is AT power I dont have any idea about that?

Is there any solution other power adapter for connecting 2 KEMs for 9971..we are having POE cisco switch....

Thanks in advance

Nithin Louis.

Power Information

The Cisco Unified IP Color Key Expansion Module for the Cisco Unified IP Phone 8961, 9951, and 9971 have the following power consumption and power scheme.

Power Consumption

48V DC, 5W per KEM

Power Scheme

At least one KEM can be powered up if the Cisco Unified IP Phone 8961, 9951, and 9971 uses AT PoE.

If the phone uses a power adapter, three KEMs can be powered up for the Cisco Unified IP Phone 9971, two KEMs can be powered up for the Cisco Unified IP Phone 9951, and one KEM can be powered up for the Cisco Unified IP Phone 8961.

A KEM cannot be powered up if the Cisco Unified IP Phone 8961, 9951, and 9971 uses AF PoE.

With AT power, the Cisco Unified IP Phones 9951 and 9971 can support two KEMs plus a USB headset or another USB device that is independently powered and only uses USB for signaling.

The Cisco Unified IP Phone 9971 needs a power cube to support three KEMS.

With AF power, the Cisco Unified IP Phones 9951 and 9971 need power cubes for any KEMS. The Cisco Unified IP Phone 8961 can support one KEM with CDP, AF power, and no power cube.

1 REPLY
Hall of Fame Super Red

Re: 9971 KEM issue with CME

Hi Nithin,

Excellent question!

802.03at is a standard of PoE that supplies a higher rating of up to 30W so that's why it can power the 2-KEMs

Cisco has been leading Power over Ethernet technology since 2000; the first generation

of Cisco prestandard PoE delivered up to 6.3W to the end devices over the Ethernet

cables that transport data traffic. This prestandard PoE supported endpoints such as

Cisco IP phone 7906G/7911G/7941G and so on.

In June 2003, the IEEE approved a standard, IEEE 802.3af, for Power over

Ethernet technology. The standard specified a 15.4W maximum power

delivery from the network device, also known as power sourcing equipment

(PSE), to an end device, also known as a powered device (PD). The average

maximum power available to the PD is 12.95W after accounting for cable loss.

This expands broader end device coverage such as Cisco IP phone 7941G-GE/7961G-GE/7985G

and wireless access points.

To support more emerging end devices with higher power requirements,

IEEE introduced new standard, 802.3at,  to scale up to 30W power delivery. This

further expands the end devices coverage to a broader range including

newer devices such as IEEE 802.11n wireless accesspoints, security

surveillance cameras, and so on. Cisco Catalyst 4500E was the first Ethernet

switch in theindustry to introduce 30W PoE technology in 2007, two years

before the IEEE 802.3at standard introduction, andlater become compliant

with the IEEE 802.3at standard when it was ratified in 2009.

From

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps4324/white_paper_c11-670993.pdf

Cheers!

Rob

"Why do the best things always disappear " 

- The Band

584
Views
0
Helpful
1
Replies
CreatePlease to create content