Provisioning Yealink T48S phones

[factor110]

Hello. We're setting up a new Zoom Phone system, so I'm a big newbie here. We have mostly Yealink T46S phones, but I have a couple of T48S as well. I've had no trouble provisioning the T46S phones, but I can not get the T48S phones to provision. I am following the steps as instructed (added the phone, downloaded and installed firmware, did a factory reset, added in the provision URL). But when I test it, it says the provisioning failed and it shows the phone offline. It also says that a factory reset is needed to provision, but I have done that multiple times now. All three of the T48S I have tried have failed. I can access the phones via the Yealink web interface, so I think they are working correctly. I am just not sure why I can't get them to provision. Any help would be greatly appreciated!

[newl]

Hi @factor110 ,

We use Poly phones in our organization, but one hurdle we encountered on some of our phones is that they had CDP (Cisco Discovery Protocol) and LLDP (Link Layer Discovery Protocol) disabled which was keeping the phones from accurately being assigned on our Voice VLAN.

Our phones were receiving an IP and were accessible from the built-in web menu; just as you described with your Yealink T48S phones, but without the VLAN being correct, they could not reach the Zoom provisioning server.

For the Polys, it was a baseband firmware issue where the defaults were different from our other models,  we had to manually make these setting changes on these phones, then the defaults were corrected once they were successfully provisioned with the Zoom firmware.

I hope that this provides some insight, reply if you have any further questions. Otherwise, consider marking this post a "Accept as Solution" so other Zoom Community members may find this solution as well!

Cheers!

[factor110]

Hi @newl ,

Thank you for the reply. I did check and LLDP and CDP are enabled. My network settings are available here if you have any other suggestions.  Yealink T48G Phone Network Advanced.pdf

[newl]

Hello @factor110 ,

Took a peek at the config, all looks to be in order.

I did see that you are using DHCP option 132. You may need to make sure that the DHCP server is sending the correct VLAN info to the phone via the 132 option.

So I would recommend a couple things:

1. Verify you have enabled option 132 on the DHCP server
2. Verify that option 132 has the correct string value for your VoIP VLAN ID
3. Check that switch port is in trunk mode (if you intend to connect a PC to the phone) 

If these seem to be set correctly, then you may have to verify that the phone is actually pulling the option 132 config. Which would likely require a packet capture via Wireshark to view the DHCP conversation (Discover>Offer>Request) process.

Hope that helps

[factor110 · Accepted solution]

Thank you for taking the time to reply. I feel like this is a little over my tech know-how lol but I have went through and compared all the settings from the model that's not working with the model that is and everything matches up.

I also just ran across an article that some Yealink phone models manufactured pre-2019 are not compatible with Zoom. I checked these three phones and they are older than expected -- manufactured in 2015. So, I think I'm just going to accept they aren't going to work and move on. Thanks, again!