Sangoma S505 Phone - When making a call the sound skips during dialing and ringing

PBX Firmware 12.7.6-1904-1.sng7
Sangoma phone S505
Vega 3000G and Vega 60G

When making internal or external calls from any Sangoma phone extension the sound during ringing will have a skip at an approximate 1 second interval. The extension being rung does not exhibit the issue. Polycom 6000 SIP conference phones do not exhibit the issue. Analog extensions on Vega gateways do not exhibit this problem. When the call is picked up the audio on both ends is fine. No call quality complaints other than low audio level. Just when initiating a call.

Correction - the issue seems to be only the S505 phone. S400 and S405 do not exhibit the issue.
The skip in the audio happens when the screen updates during the call initiation.

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Is the s505 on the latest firmware?

1.54 bundle in endpoint manager version phone says
I already have a ticket open for the S505 for low speaker phone audio and low audio outbound.

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I think this is a lag issue with the cute little animations on the screen…we’re seeing similar lag/skip/jitter on audio until the call connects, which is also when the animation stops.

Our users are complaining about this as it makes the phones sound unstable and cheap

I am running into the same problem, at least on my S705. I’m evaluating these phones again (after a bad experience the first time around) to potentially sell to customers, and this is one of the issues that’s preventing me from green-lighting it. The animation seems to be causing the audio to drop, and I can’t figure out how to turn off the animation (which isn’t really necessary for call setup anyway.)

Once the call enters an answered state, the problem goes away (even with the call timer updating), but I’m afraid we’ll have users lodging tickets about the issue thinking the problem is with our service, etc. Other brands of phones don’t do this, so I’d expect Sangoma not to either.

FWIW, I did try to open a bug report on the phone, and my bug report promptly disappeared (clicking the link given to me said I either did not have permission or it had been deleted.) I suspicion I may have been banned from opening phone bug reports though. :stuck_out_tongue:

Since there’s been no more action/feedback from Sangoma in this thread, I’ve opened a support ticket on one of my S505’s. I’ll let you know what I hear back.

I received a new firmware update to solve another ticket for low volume. This resolved some of the low volume complaints but did not fix this audio skip issue on call initiation.

Hello Cyberchaplain / Brian,

Did you hear anything back from Sangoma? I have some phones on 1.57 that are having this problem, and I am testing 1.58 released Sept 20, to see if it goes away?



We are experiencing the exact same problem with S705’s running bundle 1.58 (aka This issue has been around for a while in previous firmware iterations.

Same behavior. Dial-tone and ringing is static/stuttering, but the voice audio once connected is perfectly fine.

End users are complaining. Not sure what to do. I have opened a support ticket.

I’ve confirmed on the exact same systems, if we use the Zulu client, or any softphone client, we do NOT experience any of the issues with ringtones/dialing. That appears to rule out the PBX, and limit the issue to the phone itself.

I have not tried with other SIP phones (but I suspect the findings will be as stated above).

Below is a link to a sample of the “static”. Can you all confirm this is what you’re referring to?


I’ve confirmed this issue does NOT happen on the S405 running same/current firmware.


I can confirm that the S705 behaves in a similar fashion to the audio recorded in the small movie. We are ethernet connected / PoE,

Thank you for taking a few moments to document the behavior. My customer, who’s FreePBX server is in the cloud, gets these clicks from time to time, and expressed displeasure to us concerning them.


I’ve confirmed this issue DOES happen on the S50x and S70x models (i’ve tested them all), running same/current firmware.

I’ve confirmed this issue does NOT happen on the S405 OR S305 running same/current firmware. They appear to have different chipsets/guts/motherboard.

I’ve confirmed that in addition to hearing said static on the ringback tone while calling other parties, you also here the “static” when dialing digits when at the ready screen before initiating a call.

I’ve also confirmed you do NOT hear any static on the call itself though once you are connected to the other party.

Just confirming that the s500 & s705 phones at my site behave in the exact same way on firmware versions .55, .67, and .72.

The ticks of static seem to coincide precisely with when the screen of the phone is updated. (When making a call, there is a pretty animated graphic on the phone that shows bars going out as the phone rings; when these bars change on the display is exactly when the ticks happen.) s305, s405, and non-Sangoma phones are not affected, so it appears to be a flaw in Sangoma phones with a color display.

If nothing else, maybe include a setting to disable screen animations until the source of the problem is fixed?

Obvious silly question - how are you powering these bad boys?

The latest firmware .72 still has the static. The 505s I have are powered from HP switches and from power injectors, both exhibit the same issue.

I’ve tried POE on a Unifi Switch, Edgeswitch, Tp-Link Switch, Ubiquiti POE injectors, and the official Sangoma power supply. Doesn’t matter.

I’ve got S505’s that are ~90 days old doing this and fresh ones I ordered 2 weeks ago doing this.

Check the ticketing system. This sounds really familiar and (IIRC) was a problem Sangoma addressed and fixed. If you don’t find a commercial ticket that sounds like your problem, submit a new ticket. If you’ve tried everything we’ve suggested (and we’re all just users here) there’s nothing much more we (as users) can do with this.

Updated to .74 firmware. Static still there

Has anyone seen any updates on this issue? I’ve got one S705 phone with a EXP100 sidecar that exhibits this same issue. It’s fine for a day or two after a reboot then skipping audio starts again. Updated to the latest firmware ( 4.77 - May 2020) and still have the problem.