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New Member

Cisco 8945 and others wire configuration

Dear Experts,

                         My question may not be very rocket science kind....actually after having some connectivity problem b/w phone and switch i tried one thing by cutting the wire connecting switch and fone and i found that only four (4) wires ( ie 1 2 3 6....orange and green pair) was enough for operation of the phones....Can any one plz tell me whats are the 8 wires meant for (which one for data or packet travelling Tx & Rx and which one for Power)

                                             Is the volatge level available at the Gig ports of switches can be increased ....As in my case 2-3 fones are more than 100m away from the switch and i think is the reason that video phones are not working but the 3905 and 6921 are working......what should i do for video phone if i don wanna pur OFC or any other switch.....

@ Jamie Valecia Sir ....ur answer too

Experts Plz help.......Thanks

Everyone's tags (3)
22 REPLIES
Cisco Employee

Cisco 8945 and others wire configuration

1,2, 3 and 6 are for carrying data.. and 4,5,7,8 for power over ethernet..

STANDARDSOURCECOMMENTS

Ethernet RJ-45 connector pin number
12345678
IEEE 802.3af
using data pairs

RX

DC+

RX

DC+

TX

DC-

sparespare

TX

DC-

sparespare

Industry Standard for Embedded POE

(used by Cisco Catalyst Switches)

IEEE 802.3af
using spare pairs
RXRXTXDC+DC+TXDC-DC-Industry Standard for Embedded POE
Cisco
(old standard)
RXRXTXDC-DC-TXDC+DC+Older Cisco Products (polarity is reversed)
Cisco
(new standard)
RXRXTXDC+DC+TXDC-DC-IEEE Compliant

Cisco 8945 is a class 2 POE device. which means it consumes 7W.

You can manually define how much power you want to assign to a port using below command:

This example shows how to set the PoE consumption to 5000 milliwatts for  Fast Ethernet interface 4/1 regardless what is mandated by the 802.3af  class of the discovered device, or by any CDP packet received from the  powered device:

Switch# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z.

Switch(config)# interface fastethernet 4/1 

Switch(config-if)# power inline consumption 5000

Switch(config-if)# end


If the length of the wire is more than 100 m then it could be the cause of
your video phone not working.

Go through these documents:
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/troubleshooting/g_power_over_ethernet.html#wp1000872

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/25ew/configuration/guide/PoE.html

Cheers !!

Piyush


New Member

Cisco 8945 and others wire configuration

Dear Piyush....

                         Thank for ur awesome doc......i read few others docs also and came to knw tat for fastethernet port TDR test will show result for two pair and for gig port it will show result for all four pairs ...... wat i did today tat connected a cisco 8945 using only 2 pair (1 2 3 6) and it worked......and as wat i knw my switch is a gig port device and phone too

(i think so)......so hw did it worked on 2 pairs .....it sud have necessarily asked for all 4 pairs.....

PLZ answer SIR

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

What is the switch model u are using on which phones are connected and did u run tdr test on switch?

If yes, can u share the results.

regds,

aman

New Member

Cisco 8945 and others wire configuration

Dear Aman...

                    Its cisco 2960.......i don have the issue with the reult....i wanna knw if im running tdr test on gig port....does it matter that end device is wat type a gig device or FE device.........Cisco 8945 , 6921 etc are gig device or FE device....all 4 pairs are needed..........

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

the reason why I asked u for switch model and test tdr since I was referring the DOC which says

Except the WS-C2960-48PDL, when using the copper GigabitEthernet port of the

Catalyst 2960, one must manually set the interface to copper using the command “media rj”

before the test can be conducted.

https://supportforums.cisco.com/docs/DOC-18983.pdf

If the results on pairs are normal, then video should work.

regds,

aman

New Member

Cisco 8945 and others wire configuration

Thanx Aman..........canu u tell me if a phone is more than 100m away from switch .....hw can we drive it without putting other switch of ofc.....ne idea?

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

what is the firmware u are using for 8945 ? just to cross-check why Video is not working.

Have u connected VT Camera on 6921 for video?

regds,

aman

New Member

Cisco 8945 and others wire configuration

Aman video is not a problem Cisco 8945 is a video fone n other two 6921 r 3905 are non-video ...hence i guess they run at tat more than 100m but as 8945 requires more power its not registering

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

You have these options:

a. as suggested by Mr. Piyush, try configuring the command power inline consumption 7000

b. if u have PWR-CUBE-3 , try connecting to 8945 just to islolate the power problem.

Did u run show power inline and debug inline powerman ?

regds,

aman

New Member

Cisco 8945 and others wire configuration

Dear Aman....yeah u r rite power cube 3 will work ....

                     i have already seen the power inline and the port power is in auto max (30W) means the device will decide how much power to be taken from switch....or sud i define any other thing.....

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

I just wanted to see if power is a real problem or distance.That is the reason I wanted u to connect Power CUBE if  u have.

Also, u can try connecting the 8945 phone to any switch in network where the distance is less than 100 meters , just to troubleshoot.

What is the CUCM version u are using and 8945 phone version?

If all above steps are taken and do not get any success , try changing firmware on one of the 8945 phone.

regds,

aman

New Member

Cisco 8945 and others wire configuration

Dear Aman phone has not a problem a sit works directly on the switch...wat i feel the distance is the problem...tell me one things....

* will it work if instead of auto(3000mW) i  increase the power level consumption at that specified port. . and waats the command for that

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

try configuring the command on switch port power inline consumption 7000  and check?

regds,

aman

New Member

Cisco 8945 and others wire configuration

Dear Aman...

                    today i checked and found through the tdr test that the cable is 123m .....if i set it to 7000mW how it will run its a class 3 power device ? should i give more

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

It is a class 2 .

regds,

aman

New Member

Cisco 8945 and others wire configuration

oopss sorry 9971 is class 3 ...ok ok i will run that command.....Aman what if i make slightly high 8000mW.......as cable is 123m ....23 m xtra

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

You can give a try .Just remove/shut the other phones on same switch so as to avoid any issue on them.

regds,

aman

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

Is your problem resolved?

regds,

aman

New Member

Cisco 8945 and others wire configuration

Hi Aman....hw u ?

                    Yeah problems were solved after analyzing so many things ....

* 6921 and 3905 works on 4 wire (2 pair) 1236 ....but 9971 and 8945 doesnt work on 4 wires  until and unless u make the speed auto 100.....if its speed auto 1000 it wont work....as its not able to supply power to its accesories....

New Member

Cisco 8945 and others wire configuration

And a interesting thing happened that as the cable was more than 100m so d fone was not registering....i increased the millwatt to 8000 and it workd and got registered and again i put it bak to auto max......not its registring with same auto and same length

VIP Purple

Cisco 8945 and others wire configuration

Hi Nitesh,

Thanks for update.

Can u write in points what all u did  since I an bit confused?

If possible, share the port config and sh int output

regds,

aman

New Member

Cisco 8945 and others wire configuration

wat is did....

conf t

# test cable-configuration tdr interface gigaethernet 1/0/13

#show cable-configuration tdr interface gigaethernet 1/0/13

this will show the phone distance away from ur switch port no. 13

but if the confg

# speed auto max or 1000M ...then 9971 will  work on 8 wire and not on 4 wire...it will say unable to power the accesories

and if if u do speed auto max 100M ...then it will run on  1 2 3 6 wire

from this command i found that my phone was 123m away from switch

PLEASE rate if u found this helpful

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