Cisco 8851 add on module

[andrewokeefe]

According to the 8851 data sheet you should be able to power 2 add on modules using 802.3at POE, as long as the phone version is v08 or higher.

We are unable to get the second module to power up, anyone had this issue ?

Thanks

[Brandon Buffin]

What type of switch? Is it capable of 802.3at. Can you post "show power inline <port>"?

Brandon

[andrewokeefe]

Hi Brandon

the switch is a 3850

show power inline gi2/0/44
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi2/0/44  static off        30.0    n/a                 n/a   30.0
CORE_3850_174.16#show power inline gi2/0/43
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----

[Brandon Buffin]

OK. Should work. You have confirmed on the label on the back of the phone that the hardware is V08 or later?

[andrewokeefe]

yes, we have tried 3 8851 in all, version v08, but none work, unfortunately we haven't got any newer than v08 to test with 

[Brandon Buffin]

Have you verified that the both KEMs work if you use a power cube? Might also be worth opening a case with TAC.

[andrewokeefe]

Hi Brandon

Yes they work ok with a power cube, trouble is we have a few to roll out and we didn't buy any extra power cubes ,assumed they should work;-)

I will get a TAC case raised.

Thanks for you help

[Rob Huffman]

Hi Andrew,

The way I see the notes on the attached doc is that 2 KEM's with an 8851 require a Powercube 4;

There is also a document defect bug that relates to some of PoE info;

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvd84704

Table 3 Key Expansion Module Power

	Cisco IP Phone 8851 and 8851NR			Cisco IP Phone 8861			Cisco IP Phone 8865 aand 8865NR
Accessories	802.3af PoE	802.3at PoE	Cisco IP Phone Power Cube 4	802.3af PoE	802.3at PoE	Cisco IP Phone Power Cube 4	802.3af PoE	802.3at PoE	Cisco IP Phone Power Cube 4
1 KEM	Supported	KEM will power up as 802.3at is backwards compatible with 802.3af.	Supported	Not supported	Supported	Supported	Not supported	Supported	Supported
2 KEM	Not supported	Not supported	Supported	Not supported	Supported	Supported	Not supported	Supported	Supported
3 KEM	Not supported	Not supported	Not Applicable	Not supported	Supported	Supported	Not supported	Supported	Supported
1 KEM + tablet charging	Not supported	Not supported	Not supported	Not supported	Supported	Supported	Not supported	Supported	Supported
2 KEM + tablet charging	Not supported	Not supported	Not supported	Not supported	Not supported	Supported	Not supported	Not supported	Supported
3 KEM + tablet charging	Not supported	Not supported	Not supported	Not supported	Not supported	Supported	Not supported	Not supported	Supported
Smart phone charging (No KEM attached)	Yes	Yes	Not supported	Yes	Yes	Not supported	Yes	Yes	Yes
Tablet charging	Yes	Yes	Not supported	Yes	Yes	Not supported	Yes	Yes	Yes

From

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cuipph/8800-series/english/adminguide/P881_BK_C136782F_00_cisco-ip-phone-8800_series/P881_BK_C136782F_00_cisco-ip-phone-8811-8841_chapter_0111.html#IP8K_TP_K8B7A60A_00

[Brandon Buffin]

Rob,

That was true of older 8851 phones. Did you see the note here regarding V08 and newer phones:

http://www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/ip-phone-8800-series-key-expansion-module/datasheet-c78-732356.html

Brandon

[Rob Huffman]

Hey Brandon,

Good info my friend! (+5). I'll keep looking for a better answer here.

Cheers!

Rob

[Amit23]

Hello Andrew,

i saw your post and we are facing similar to your issue.

we have one 8851 with 1 KEM audio 28 button but it is not powering up when connection.

in phone accessories it is showing disabled by administrator.

I checked all required option and enabled in CUCM but still no success.

Please let me know if need any other step for it.

we have cucm 11.5.X and connected audio 28 button KEM with power cube-4 .

[mraj_ Seed]

hi Amit, did you manage to resolve the issue , am in same situation