Having some issues with very start of the 4747 test on Grandstream HT818V2.
Press a DTMF button, can’t hear the number replayed back. “one”, “two”…etc.
Seems like comfort noise or echo cancelling is interfering.
Wireshark is not reporting any missing or excessive jitter.
I’ve had that exact thing happen on a different Grandstream ATA, and in my case the problem ended up being the DTMF method. The device was set to SIP INFO, and switching it over to RFC2833 immediately fixed the issue. After that, the 4747 test started reading back “one”, “two”, etc. normally.
If changing the DTMF method doesn’t clear it up, you can temporarily turn off Echo Cancellation and Comfort Noise just for testing. Those DSP features can sometimes suppress the short audio burst that plays the spoken digit. Once you confirm the cause, you can re‑enable whatever you need.
Thanks redbaron, unfortunately that did not resolve the issue Tried turning off comfort and echo.
Rebooted ATA, still no go.
Contacting Grandstream to see if their V2 firmware is at fault.
Did you also try disabling VAD on the HT818V2? I’m pretty sure that model includes it, and it can cause clipping. Also, are you running PCMU (G.711u) only? The compressed codecs can sometimes interfere.
Comfort the same as VAD?
Comfort Noise and VAD aren’t the same, but they work together. VAD detects silence, and Comfort Noise activates when VAD triggers. Usually if CNG is off, VAD is off too, but I’ve had Grandstream ATAs where the firmware treated them as separate settings. On some units, selecting G.711u‑Annex2 also automatically turned VAD on even when the CNG/VAD box was off, which caused audio issues. If you don’t see VAD in your UI or Annex2 listed with your codecs, your device likely doesn’t support it. I’ve seen it on some V1 models, but I’m not sure it was ever included in the newer V2 units.