support wiki

helpful humans at 423-456-6700

User Tools

Site Tools


System Setup
Getting Started
Setup Wizard
Porting Numbers
Caller ID
Special Projects

Network Introduction
Recommended Equipment
Ideal Network Setup
Firewall/Network Configuration
  Routers That Should Not Be Used
Ubiquiti ER X Configs
How To Disable SIP ALG
Networking Disasters
OpenVPN on Grandstream Phones
Port Forwarding / External Remote Phones

Customer Admin Portal
  Basic Mode
  Hold Music
  Advanced Mode
  PA Ring Tone
My Services
  International Calling
  Call Recordings
My Account
  Account Info

Functions & Advanced Features
Schedule Override
External Storage: USB
Hold vs Park
Hunt Groups
Line Emulation
Relay/Door/Alarm Control
Feature Code List
Grandstream Wave

Hello Hub V2
Hello Hub Nano - Cloud Connector
Supported Phones (Auto-Config)
Grandstream HT801/802 Tricks
Pairing Instructions for DP750/752
Grandstream WP820
PA Speaker (SIP) Configuration

Hello Hub V1
Hello Hub V1 Battery Removal
Manual Config Phones

Switching Loops
Email Notes

Payment Policy

System Variants
System & Hardware Variants

Terms and Conditions
Software Licensing

Blog and Rants
Recording Phone Calls & Conversations



30 second VoIP/SIP call drops

An edited copy of an email I just sent regarding calls dropping at 30 seconds, sometimes.

Re: 30 second call drop issue:

It's a common bug in some older commodity routers that all borrowed the same core firmware years ago. We don't see it as often as we used to, but we still do. You've got a good router on that site, I doubt that's got that glitch, but that's why we start there. Worth knowing, that problem is consistent if it exists, every call, at exactly 30 seconds (maybe 32). 

Other devices will drop a call at about 30 seconds, for different reasons, intermittently. WiFi AP's especially if the phones are WiFi. They sometimes have connection tracking limits or are just overloaded. Then there are two things that just completely futz up a network we run into: Sonos WiFi speakers and Mesh WiFi repeaters (Orbi, Google Mesh AP). The WiFi meshes and repeaters often cause “loops” and break all connections and reset for just a moment when they do, or the ethernet switch involved detects the loop and resets.

I'd start with the basics and work up:   

Do calls from 1 extension onsite to another break at 30 seconds? If so, that path/traffic is from phone to hello Hub to phone. I'd look at local networking gear. Maybe even a specific phone or ethernet connection.  

If that's OK, is it calls to/from landlines (POTS or VoIP) or mobiles? Just one call, or do all calls happening at the same time drop? If all, something upstream from the Hello Hub is breaking the connection: ethernet switch→router→modem→ISP's gear….

I checked out his system last night while checking a problem with fax connections.  It looked good but I noticed it was missing some audio prompts when I made test calls (002 and 000) so I sent it an updated sound files (a zip).   Transfer speed was < 400KB/s. Took over 10 minutes to transfer. I just did it to my home system, sent 252MB in 8 seconds… 28MB/S  – This is probably an indicator of not a great ISP/network connection at . I'd be curious to know what kind of speeds to get from a speed test and what you are paying your ISP for.  This was about 10:30pm last night, in case that helps. Maybe you were doing a massive backup/download?

And to test again: I called this morning, two-way audio test ( dial 002 ) sounded great, and I also listened to hold music for about 3 minutes, also sounded great.  I also just sent the (252MB) to the system and it took 30 seconds, at 8MB/s. - That's a big difference from last night.  is there something variable in the network.ISP, or behavior (downloads, etc..). Maybe that's a clue? 

In summary: I'd start with logging the 30 second call problem: What phone, to/from what caller. My assumption is they are outside callers. Are they calling while driving down the road? Or are these solid calls to a fixed location that drop. How was the audio quality of the call before the drop? 

Diving into deep diagnostics mode:  With the external phone numbers involved and an approximate time and if I get it within 48 hours, I can grab switch logs and see which end dropped the call. If the other parties are dropping, not much I can do but identify it. If the Hello Hub side drops the call, it may be something we can find and address. 


blog/30_second_voip_sip_call_drops.txt · Last modified: 2022/06/10 16:46 by mike