PnP phones not showing up

Flipper

Gold Partner
Joined
May 29, 2026
Messages
7
Reaction score
2
I set up a new T73W to be a router phone and it is currently registered to the hosted system..
I confirmed DHCP option 66 is correct.
I did a PCAP on the router phone and see the broadcast of the second phone. (so it is working across the local switch)

I would expect that the 2nd phone would then show up in the PnP table.
Am I missing anything?
 
Ok but did you check the tunnel logs in the PBX and checked if the subscribe message arrived?

In the PBX you need to access the menu —> PNP phones.

Make sure the phones are in the same local LAN as the sbc
 
Last edited:
Yes the two phones are on the same switch and both are on the same Subnet 192.168.214.0.
No I did not do a PCAP at the PBX.
The router phone is getting the 224.0.1.75 SIP 567 Request: SUBSCRIBE sip:[email protected]. Shouldn't the router phone then route via a tunnel to the PBX? The packet arrived at the router phone at 13:32:50 No packets were ever sent to 192.168.214.4 and the next packet sent from 192.168.214.2 ( the router phone ) was at 13:33:03 where it re-registered.
 
Ok, as first step, check the sbc connectivity is stable and wired not WiFi or anything similar, in the PBX navigate to the sbc trunk and check it has populated the sbc local and public IPs.

Check the phones are using the recommended firmware https://www.3cx.com/docs/phone-firmwares/

Set the PBX logs to verbose mode, perform a factory reset on the phone and when it finishes the boot process, get the support info —-> open the logs folder and check the tunnel log, do you see the subscribe there?
 
For the record, only been 3CX for a year, and first time trying the PnP feature.
Thanks for the breadcrumb! The phone is registered, but the SBC is down. I saw a firmware update is available for the phone. After the update, SBC is showing up, factory defaulted the 2nd phone. 2nd phone is stuck on the Password screen. Edit: even though on password screen it is now in PnP phone list. Curious that teh router phone that is assigned to a user is also on the PnP list now.
 
Check if the phone’s public IP is blacklisted from the old firmware. Probably not if you see it… Recommendation is to upgrade firmware first, or there’s now a checkbox to auto upgrade when provisioning.
 
Too much conflicting information here. I think you should start from scratch:

1. Delete all phones from 3CX and factory reset them. Now power them all down. Also delete all PnP page entries, they are now invalid.

2. Add the first router as per our guides for your model. Plug it in so it can autoconfigure.

3. Then add the next router phone and so on.

4. When you run out of router phones and wanna add normal phones, start plugging them in and when they end up on the password screen, you can then check the PnP page and they will appear there.


I confirmed DHCP option 66 is correct.
I don't know what you mean by this. What does correct mean?
You don't need such a thing in your case anyway.
 

Forum statistics

Threads
112,200
Messages
591,235
Members
165,260
Latest member
natefraser