7841 Connection Speed

[Michael Horton]

I have a few 7841s (sip78xx.12-5-1SR1-4) that are connecting at 1G per spec and some are only connection at 100M. The cabling is good and there is no distance problem between the phones and the switches (all 1G POE switch ports patched to Cat-6 horizontal cabling).  Other than the fact that the phone is spec'd at 1G, my main concern is that I'll be daisy-chaining PCs off of the phones and would like to have the higher connection speed for them. Any help to resolve, or at least explain, this issue would be greatly appreciated.

[Leo Laohoo]

Pick a phone that is running 100 Mbps only and then run a TDR from the switch:
1. Command: test cable tdr interface <PORT>;
2. Wait for about 5 to 7 seconds for the process to run;
3. Command: show cable tdr interface <PORT>; and
4. Post the complete output to #3.

[Michael Horton]

Leo,

This is the result of my cable test for one of the phones connecting at 100M:

Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi1/0/21 1000M

Pair A 71 +/- 10 meters Pair B Normal
Pair B 71 +/- 10 meters Pair A Normal
Pair C 71 +/- 10 meters Pair D Normal
Pair D 71 +/- 10 meters Pair C Normal

[Leo Laohoo]

Result says the downstream client is negotiated to 1 Gbps.

[inderpreetsingh23 · Accepted solution]

Hi Michael,

For the phones which are negotiating on 100M can you please what is the setting on switch end and phone page? As per the best practice the settings on CUCM and switch end should be Auto/Auto.

If you need to change settings on the phone itself, go to the phone page then select Switch Port/PC Port remote configuration and select 1000/Full.

Hope this helps.

Thanks

[Michael Horton]

Thanks for the help! I've been deploying the 7800 series phones for a couple of years now and have never even considered modifying that setting, thinking that it did something different. I guess I need to do a bit more of RTFMing! After making the changes all of my 7841s are connecting at 1G.

Thanks again!