Slow Yealink T23G Phones after upgrade to firmware V81

Anybody also experiencing that their Yealink phones (T23G) have become slower after upgrading to firmware V81?

When pressing digits on the phone it often takes two seconds or more for the phone to react. Same thing when hanging up a call, makes you wonder if you hung up at all cause the phone’s reaction is delayed, which is unusual and didn’t happen on previous firmware.
When I go back to V80, the problem seems to be gone.

Not sure why, is it issues with memory?
A reboot improves the situation for a while.

It is happening on ALL of my phones.
Anybody with the same experience?

Short answer: No!

You can either go to Yealink for support or do it yourself. First get time in sync - ntp for everything - FreePBX, phones and your PC. Logs are bloody useless if timestamps are random.

Get two phones setup - one with 80 and one with 81. Make sure the problem is demonstrable and consistent before you do anything else. Get the IP address of each phone and note it down.

On your PBX get to the console and run (substituting the IP of the “ok” phone), you may have to “yum install tcpdump”:

# tcpdump -s 65535 -w ok1.pcap host

Do a quick test that is “OK”. This is your baseline. Be as quick as you can to limit the number of packets. Press ctrl-c to stop tcpdump.

Start another tcpdump session for notok1.pcap and do the same but with the IP of the notok phone and demo the problem with the notok phone.

Install Wireshark on your PC and transfer the .pcap files over to it. You can use winscp if your are a Windows user or if you know how to do it you could get Samba up on the PBX and map/mount a share and read the .pcaps directly. You could use a smart phone to video each test and by watching an accurate clock you can correlate packet timestamps to actions. Wireshark also has a lot of diagnostic tools built in to help analysis but I’ll grant you it can be hard to get to grips with if you’ve never seen it.

Also, Yealinks have a tonne of diagnostic functions and logging built in which can be enabled and if I recall correctly (I don’t have one to hand right now) but I think they can run packet capture themselves. Again, demo the problem and lack of it and compare logs.

You can’t ask a question like “Not sure why, is it issues with memory?” and expect an instant answer. Its pretty unlikely that Yealink are going to release a completely broken firmware so you have to either do some detective work and ask specific questions on forums like these or get some commercial support.


Thank you.
I will try and see if any of the diagnostic functions on the Yealink itself can be of use here.
Any tcpdump and packet capture done on the server won’t help me cause I experience the phone being slow even before any packets are sent.
Usually when pressing a digit you instantly hear a beep and you see the entered digit on the display. With V81 on my T23G phones this is a few seconds delayed, which is quite irritating to the user.
It’s not happening consistently with every digit you enter but the phone’s slower reaction is quite noticeable and definitely not happening on V80 firmware.

Not really, Yealink has done it before.

As several users have been reporting this to me, I wanted to see if others are having the same problem.