S100 (27) yealink 42S
Volume seems low during calls, and after you speak I hear a hiss at the PBX side after speaking then goes away, When using VOIP MS trunks no issue
T42S - comfort Nosie disabled - echo cancelation on
I have echo cancelation on in the PBX as well should I disable one ?
And suggestion on adjusting CO lines sound quality
Greg
There is another factor, each line property might be not the same as standard due to the circumstance it relies. We called it impedance match, and we suggest you try this rather technical guide: https://support.yeastar.com/hc/en-us/articles/360020425554-FXO-Impedance-Match-Tool-Instruction
Hi Gregery, did you try to connect the line with analog phone directly? To test if the line is good or not.
Yes Lines are clean on butt set.
Do you leave the echo cancelation on in the PBX and in the Yealink handset?
Echo canceler - It is not a question of should at this point, as we do not know if there is echo. You can remove it as a test at any time and see if there is echo or not. There are different types of echo and where the echo can occur. If line echo, it is usually associated to an impedance mismatch between the PBX and the POTS line. The echo is caused by too much energy entering the POTS line from the PBX such that some of that same energy is reflected back and you end up hearing yourself somewhat delayed afterwards (echo).
Sidetone info can be found here:
https://en.wikipedia.org/wiki/Sidetone
Please note the section about "leaving enough feedback signal to assure the user that the phone is really working". This is akin to when taking the handset off hook and simply speaking into the mic and getting that feedback in the earpiece that it is working.
As you did not mention that callers have a hard time hearing you, but that the volume seems low only on your end, then take a look in the PBX and the phones for a RX gain setting. This is a setting that will adjust the analog amplitude for volume on the receive side of the call.
The hiss you hear is somewhat subjective as some may hear, some may not and either may not find it objectionable. There will always be some amount of white noise, but the key is such that the noise would hopefully be so low as to be unnoticeable. This is a S/N ratio and the issue may be that it is on the telephone line, in the adpater, PBX, or possibly inducted if it is really hum. What do extension to extension call do?
Update - Call reports of sounding tinny and with shhh
The sounding tinny I am not sure about and the shhhh noise seems to be the echo canceler. So when the customer is speaking on the Yealink 42S you can hear a shhhh noise as well and its pretty loud I have attached the packet cap any suggestions.
I was told the line voltage may not be correct does any one know what the voltage needs to be ?
((handset to handset is good and when using the SIP trunk is good problem only with analog lines))
https://1drv.ms/f/s!AnKiCIV8qZ49gaAMJvcF839oPQIMvA
Another thing I forgot to mention - When I first installed the PBX I set all phones up with static IP address's I notice that the Voicemail button wasn't programmed with the *2 so I added it logging into the phone. Since then I changed the Phones to DHCP and used the auto provision but didn't factory default the phones. Is it possible the yealink phones didn't get the right config and that's causing some auto issues ?
I checked the pcap and listened to the call. I heard nothing of what you described. I heard you indicate that you could hear it, but that the other side would not be able to. There is not much I can suggest other than to insure you have the latest firmware in the phone and if possible, you might try another phone to see if isolated to your phone. You could also try using Linkus or another make & model phone and perhaps that testing will isolate.
You had mentioned (in the call) turning off the echo canceler, if you did, was there any difference?
I checked the pcap and listened to the call. I heard nothing of what you described. I heard you indicate that you could hear it, but that the other side would not be able to. There is not much I can suggest other than to insure you have the latest firmware in the phone and if possible, you might try another phone to see if isolated to your phone. You could also try using Linkus or another make & model phone and perhaps that testing will isolate.
You had mentioned (in the call) turning off the echo canceler, if you did, was there any difference?
First thank-you for taking the time to help
Turning off the echo canceler cause the echo to be very high ever word I said I heard back in the ear piece.
Larry at the 64 second mark after I was done talking you can hear on the capture two SHHH then SHHH noise its not overly loud on the capture but on the handset its a lot more noticeable
Larry does the phone pull audio set up during auto provision?
If you are hearing echo of yourself, then lower the TX gain on the O2 module settings. You should set the phone back to its default settings for TX & RX gain. You want to have no echo and preferably without the echo canceler.
Looking at the default provisioning template, it does not appear that any audio related settings are included.
Do we have any info on conditioning the line to the right voltage to match the Yeastar. The S series does not have the best sound quality on analog lines , they sound tinny and hollow.
Analog lines - hollow sounding, and tinny
SIP Trunks - fuller sounding and more full sounding.
The noise from the echo canceler really is not good compare to the other systems I have put in. I am getting a Grandstream FXO gateway and try it to compare voice quality
It is not a voltage thing. I am not sure that it is fair to expect analog to have the same quality as VoIP. SIP is a digital signal and immune to some of the issues associated to analog, static being one such anomaly as are white noise and hum. These are analog issues that a digital signal cannot introduce or cause of its own accord. The issues can be created elsewhere in the analog environment and conveyed into the digital carriage which can observed when converted back into analog and heard.
Further, the quality of the audio being heard can be influenced by the voice codec in use. G711 will usually "sound" better than G729 and G722 will sound better than either. This is all influenced by bit rates, sampling rates and other factors involved in the codecs as to how they encode and decode analog signals.
I have not worked with the O2 module. I have one, but its just not high on my priority list. My other issue is that I have no POTS lines. I have a POTS line simulator, which I use fairly often, but its signal is so pure, I doubt that it would mimic your situation.
So, while I don't think analog will have the same quality as SIP, this is not to say that what you get with the O2 cannot be improved.
My only advice is that if you did not heed my suggestion about reducing the TX gain in the O2 module, then you may still get echo on the others. They all use software echo cancelers with many not being adjustable with regard to tail length. They can only do so much, so the best approach with any is to disable the canceler, set the phone back to its default TX and RX gain settings and then make calls and adjust the TX gain to the extent that the echo is minimized and the other end can still hear you without issue. Once done, then turn the canceler back on. Then check the receive sound and adjust the RX gain on the O2 card first. When you adjust the gain on the phone without doing the interface first, you are also amplifying the noise as well. It is a balancing act as the O2 will do the same, but with the phone set at the default, this is usually the level that many call unity gain which is that the levels coming in from the O2 module are the same level that the phone will provide. The phone is neither forced to overdrive a weak signal or attenuate a too strong signal. You want to set the O2 RX gain to a level that the phone will deliver at a reasonable level to the average listener.
Good luck
Larry thanks again I understand the testing now with the TX gain and echo canceler off. I did play with the RX and TX gain today I had the TX gain down to a -20 and it did sound better but the other end could not hear me very well. I do realize SIP will sound better but I am comparing my 30 plus installs over other phone systems I put in on CO lines and they all sound noticeable better. I will be working more on this Friday and will update my final results and findings.
I had not seen Pixy's post earlier about impedance match. Have you done this process? If not, then it is needed. The usually acceptable standard for a traditional POTS line is 600 Ohms in the US. However, this is oftentimes not the case. Line condition, distance and other factors may cause variations as to what is seen and even between lines. It is most often associated to Echo as impedance had a direct relation as to the amount of energy that can be absorbed by a line before reflections (echo) occur. I am surprised that this is not included in the GUI setup rather than having to SSH into the system.
The tinny sound was never my focus, as that is a tonal aspect that is subjective and whose quality may be somewhat impacted by addressing the TX, RX levels and echo, but only in as much as the settings I addressed would hopefully resolve some of the other issues which might make the resulting experience better.
As an aside, the post indicates 4 O2 modules implying a possible 8 POTS lines. Were you able to test all the POTS and did all have the same issues or were some better than others?
Do I take it that the other 30 installs used something other than O2 modules?
Larry, Yes 30 plus installs on Allworx with Pots lines. I ran the suggestion from Pixy Xie and it does help a little but there is something off with the Yeastar YO2 cards or there software when it comes to the quality of the call on analog lines. I am only comparing from past installs with other systems on POTS. If you make a call on a CO line with the Yeastar and a Yealink phone you hear alot hiss/shhhhh noise when you speak from the handset and once talking it continues for a few seconds. The Allworx PBX on CO lines you hear nothing in back ground noise to be honest POTS and SIP trunking sound about the same.
If you play back the attached packet capture and isolate were I have it noted in the pick I have provided why is there so much white noise/hiss/shhh and its very noticeable
https://1drv.ms/f/s!AnKiCIV8qZ49gaAMJvcF839oPQIMvA
Well. I am now curious. If I get time in the next day or so, I will install the O2 card and hook up the simulator and see what results I get. At first I thought I had uncovered the issue to be the CN which would be generated during silence by a VAD (which I assume to be somewhere in the S PBX), but looking at the timestamps and comparing to the duration (the RTP started at 27.7 and ended at 65.2 = 37.5 and then comparing to the RTP timestamps of 80 starting and 299920 ending = and dividing by 8000 = 37.48, it really doesn't appear to be such. I assumed this because of the silence (and no noise during the periods of no speech, but as I cannot see the same during the voice activity, it is unknown if the noise is present during that time or not.
I finally got around to is. I did not have a O2 module, but a SO module. I assume the circuitry is the same between the two for the FXO ports. I hooked up my line simulator and as you can see from the below, there was nothing like what you see:
Confusing for sure I have a open ticket on this issue I will keep everyone update with the findings . No one on hear is running YO2 cards with CO lines having this issue ?
Greg
hi, I have 4 s20 with the 02 module on board, all with the same problem, did you solve?
Fabio
I solved the problem by switching all the customers to SIP trunking the Yeastar S series is extremely bad with analog lines almost unusable in some cases period. Every location with analog lines the PBX sound quality is poor except in rare locations