loud buzzing sound on intercom calls

[Stewart]

I have a new setup with T26P phones running 6.70.0.140. On about 25% of intercom calls (apparently at random), when the caller is also using speakerphone, e.g. pressing intercom button when on-hook, a continuous loud buzzing is heard. Sometimes the caller hears the noise, sometimes the called party. If either party lifts the handset, or if the party getting the buzz speaks loudly, the buzz stops and normal conversation can take place. The problem does not occur if the caller is using the handset, or on non-intercom calls. The buzz occurs after the normal intercom warning beep is played.

Codec is G.722; Asterisk is set to re-invite the audio and I've confirmed that audio flows directly between the phones (on the same LAN).

Has anyone else seen this problem?

Thanks,

Stewart

[Yealink Support]

Hi Stewart,
1. Did you try to reset to factory default?
2. Could you upgrade to our V71 beta firmware to check whether the problem is resolved?
ftp://yealinkftp:yealinkftp@ftp.yealink.....0.130.rom
3. If the problem is still, could you provide PCAP trace, syslog(level 6) and config.bin file to us, so we can analyze?
Before you export the syslog, please set log level as 6, and reboot the phone, then click Start,and reproduce the issue, then click Stop,and export the trace, syslog, config,bin to us.
(About where to export these files, please refer to attached screenshot.)
These three files are very important for us, hope you can kindly understand.
Thanks.

[vgdynamic]

I'm experiencing a random, very loud buzz on our system, as well. We use T28P (3) and T38G (5). It is exactly as Stewart describes (same codec, same symptoms), although not as often for us (maybe 10% of the time). We are using FreePBX 2.11.0.10 on Asterisk 11.2.1. The 38s are on firmware 38.70.0.143 and the 28s are on 2.70.0.130. It happens between any model of phone (38 -> 38, 38 -> 28, 28 -> 28, 28 -> 38), and as Stewart mentioned, it's seemingly random as to which party gets the buzzing.

I don't see any kind of pattern, so reproducing the issue reliably is not possible at this point.

[briankelly63]

It's hard to get anything that's operating in an almost pure digital environment to "buzz" these days. Could be a mis-match in Codec that occurs randomly but until its get more consistent it's going to be difficult to isolate. If it does get more consistent or seems to be happening to the person who makes the most calls I would set up Wireshark to record the RTP streams, which could be targeted at the phones IP address or the servers IP. I'd also look for a POE or power supply issue.

As I re-read the original description the part that gets my attention is that when you pick up the handsets the problem goes away. The phones microphone is very sensitive. Anyway it could be picking up something like PC vibration or fan noise on or through the desk?

[braymond]

The buzz does not seem to be coming from the RTP stream but more from the phone itself. I ran into this buzz on a T28P that had a headset connected to it. I initially thought it was the EHS (since it uses a Jabra wireless headset) so I connected a corded one and if you answered the phone quickly, the buzz could be heard.

I then unplugged the headset cable and no more buzz. If we answer after the second ring, no buzz.

But then I got report from my customer (last Friday) that they start hearing buzz upon answering. Those phones are T26P and no headset. They've been running for almost a month now. I have restarted the phones except one and will check with the customer if the buzz is gone on those I restarted.

I am using the V71 firmware and I use Freeswitch as my PBX. But it is unlikely an issue coming from the RTP; this buzz is more like an induction within the phone.

I'll go onsite in a few days if the problem still exists so I can collect pcap, syslog and config.bin. I will even record the sound so that people can hear what it does ... pretty annoying sound.

[pmterp]

Any make progress on this? I've just gotten my first report of the problem and can't seem to figure it out. It's happening on 2 of 6 phones in this office and only when using the handset, on speaker the problem does not exist. I've updated FW to .165 and it's still happening.

[Yealink Support]

Hi pmterp,

Do you test other handsets in the phone?
Does the issue still exist? If yes, please contact with your distributor for further technical or RMA support.
If not, please replace a new handset.

[ndt4u]

I bought a T46G to use as a demo, and it has a buzz through the handset. I have had it on different systems and it makes the same noise on handset. It is a low humm. Speaker sounds good. Sounds good with a Norstar handset, but may be more muted. This handset makes the noise even with the hookswitch held down, like the handset has battery to it even when hung up. Bad handset? Bad Phone? Ant idea why handset would be live when hung up?

[Yealink Support]

Hi ndt4u,

Do you test other handset in Yealink phone? Please contact your distributor for help, they can support a new handset for test and you can make a RMA if the handset is broken.

[braymond]

The buzz seems to come from the twisted wires inside the handset. They have twisted and looped the red, green, yellow and black near the microphone.

What you can do is take the little rubber out to access the philip screw, remove the screw and take the handset apart. Then un-twist the wires so the red/green pair is not twisted with the yellow/black pair.

If you keep the handset plugged to the phone, the hummm should go away as soon as you start un-twisting the wires.

Looks like this twist and loop is making the wires acting like a coil.

At least it worked for me.

Thanks,
Benoit