Question about wiring for Cisco 9971 phone

ronald.nutter · ‎09-12-2013

I am in the process of deploying some 9971 phones. I have run into a problem where there appears to be a wiring problem on a particular cable run. The phone keeps trying to boot and connect to the network but never completes the process. If I move the phone to another outlet, it works just fine. I have swapped out the patch cables at the desk end and the wiring close end of the cable run. This tells me that the problem is in the rj45 jacks at one of the cable or the other. I ran the tdr diagnostic commands and I am showing an open pair (pair D). Is there a way I can get the switch to route power over one of the other pairs ?

If not, i am looking at a process of several weeks to get the wiring group involved to fix the problem because that has been outsourced to an outside organization.

Thanks,

Ron

Chris Deren · ‎09-12-2013

No, you will need to solve the wiring issue or deploy 9971 wirelessly in that area.

HTH,

Chris

Nitesh Prabhakar · ‎09-12-2013

ronald do one thing.......its for sure it will work

juz log in that switchport.....and do speed auto 100m

connect the 1236 only ...that is orange white to orange white....

orange to orange...

green white to green

and green to green

after doing 100m 9971 is working on 4 wire(A and B pair only )....will work

plz rate if found helpful

Chris Deren · ‎09-12-2013

Sure you can do that as 100Mb does not use other pairs, but you would be downgrading the speed to the PC connected to the phone 100Mb, in any case might work for you if you are OK with it, assuming that wires 4,5,7,8 are the broken ones.

HTH,

Chris

Nitesh Prabhakar · ‎09-12-2013

100mbps is not a small speed sir.......u will use video call or watever its a local lan speed....i tried no issue of freezing and all if u use 100m....still if u want to use 1000m u can but all pair is needed as it becomes gig device.....

u can directly connect 9971 on switch with a patch cord sir

Please rate if its helpful

Nitesh Prabhakar · ‎09-12-2013

as u are saying ur D pair is open.....then juz change the wire simple

Chris Deren · ‎09-12-2013

I disagree, 100Mb is obviously a lot more bandwidth a phone would ever need, but if you have a PC connected to the phone on a 1Gig network then the phone becomes a bottleneck. If the user only uses the PC for browsing and email it is not a problem, but if he/she needs large file transfers for example of blueprints, images, etc then they would not be happy losing their speed.

Chris

Nitesh Prabhakar · ‎09-12-2013

yeeah chris i agree..........but if u r finding that wid tdr test D pair is open why dont u chage d cable sir...as u don wanted to chage the cable i suggested dis...........so that u can bypass D pair can run same fone with the same cable

jz make it 100m and see whether it gets registered or not...for a check

Rate plz if its helful

Chris Deren · ‎09-12-2013

What's up with all this abbreviated writing, really hard to make it out. Are you texting?

Chris

Nitesh Prabhakar · ‎09-12-2013

hahahhahhaa dont mind........sorry

I meant to say juz go to the switch port and make the speed 100m if your phone works ....means it was a cable issue

Rate if its helpful

Leo Laohoo · ‎09-12-2013

I ran the tdr diagnostic commands and I am showing an open pair (pair D).

If Pair "D", which controls GigabitEthernet, is faulty, then it's as simple as configuring the port to negotiate to 10/100 Mbps.

ronald.nutter · ‎09-16-2013

Thanks for all the replies. In addition to the tests I had run, I also tried a new phone just to make sure I didnt have something squirly there. The new phone showed the same problems.

I brought in my old faithful Fluke Enterprise Lanmeter 683. It didnt see any problems. Being that old it doesnt have the ability to test at 1GB. Based on the the posts in this thread, I locked the port down to 100MB/Full Duplex and the phone comes up as expected.

I want to find a docuement or something that explains the difference in wire use or something that I can take to my boss to help explain this. Without something like that, he will never believe me.

Thanks for all the help,

Ron

Chris Deren · ‎09-16-2013

See table "802.3af Standards A and B" as it should make it clear.

http://en.wikipedia.org/wiki/Power_over_Ethernet

HTH, please rate all useful posts!

Chris

Nitesh Prabhakar · ‎09-16-2013

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

STANDARD	SOURCE								COMMENTS
	Ethernet RJ-45 connector pin number
	1	2	3	4	5	6	7	8
IEEE 802.3af using data pairs	RX DC+	RX DC+	TX DC-	spare	spare	TX DC-	spare	spare	Industry Standard for Embedded POE (used by Cisco Catalyst Switches)
IEEE 802.3af using spare pairs	RX	RX	TX	DC+	DC+	TX	DC-	DC-	Industry Standard for Embedded POE
Cisco (old standard)	RX	RX	TX	DC-	DC-	TX	DC+	DC+	Older Cisco Products (polarity is reversed)
Cisco (new standard)	RX	RX	TX	DC+	DC+	TX	DC-	DC-	IEEE Compliant

dear Nutter.........hope it will somehw work

please rate if u find my posts helpful