What you’re seeing
- A caller can be heard but cannot hear you, or the reverse.
- Calls disconnect at almost exactly 30 or 32 seconds, or at a fixed time every call.
- Inbound calls ring the desk phone but go silent or fail when answered.
- Phones register fine and show a dial tone, but audio problems start once the call connects.
- The trouble began after a new firewall, router, ISP or firmware update was installed.
Common causes
Every environment is different, but these are the causes our engineers find most often:
- SIP ALG on the router or firewall is rewriting call signaling and breaking the audio path.
- Audio traffic on RTP ports is blocked or not forwarded through the firewall.
- Double NAT means the phone system advertises the wrong address, so return audio goes nowhere.
- UDP session timeouts on the firewall are too short and close the connection mid-call.
- The phone or PBX is configured with the wrong public IP or NAT settings for your network.
- QoS is missing, so voice traffic is dropped when the connection is congested.
Why it matters
Phones are still how many customers reach a small business, and calls that drop or go silent can cost sales and damage trust immediately. Callers rarely ring back after a failed call; they move to a competitor. Staff waste time apologizing, calling back and switching to cell phones. Because the problem often starts after a network change, it can be hard to pin down, and the phone provider and the IT person may each blame the other while the business keeps losing calls.
How AskTechGurus fixes it
Skip the trial and error. A certified engineer works on your actual system, finds the root cause, and fixes it properly.
Tell us what’s happening
Submit a ticket in about two minutes. Paste the error, describe what changed, and pick your tier. No charge to submit.
A certified engineer diagnoses it
A vetted, US-based systems engineer claims your ticket, usually within minutes during business hours, and investigates over a secure remote session you can watch and end at any time.
Fixed and verified with you
The engineer resolves the root cause and confirms with you that it’s working. You don’t just get a workaround, and you get a plain-English summary of what was wrong.
Pay only when it’s resolved
Fixed price from $99, invoiced only after you approve the fix. If it isn’t resolved, you don’t pay.
Frequently asked questions
Why do calls drop at 30 seconds exactly?
A fixed cutoff usually means the phone system is waiting for a confirmation that never arrives because the network changed or blocked part of the call signaling. It is a configuration problem, not a bad phone.
Is it our phone provider or our network?
Most one-way audio and timed drops come from the local router or firewall. Testing from another connection, such as a mobile hotspot, often shows which side is at fault.
Can you work with our VoIP provider?
Yes. A certified US engineer can review your firewall settings and coordinate with your provider's requirements during a remote secure session. Service starts at $99 and you pay only when calls work properly.