No Audio or One-Way Audio on Akuvox Intercom: Full Troubleshooting Guide
In high-stakes security, silence is a failure. This encyclopedic deep-dive covers every potential failure—from SIP packet structure to hardware mic-gaskets—ensuring your Akuvox system communicates flawlessly in any environment.
1. Introduction: Why Voice is the Heart of Access Control
When you install an Akuvox SIP Intercom, you aren’t just installing a doorbell; you are installing a specialized VoIP endpoint. While video provides context, it is the audio that provides intent. Learn more about video intercoms vs smart doorbells for your home. Without clear, two-way communication, verifying the identity of a visitor, courier, or potential intruder becomes an impossible task.
The challenge with digital audio is its fragility. Unlike legacy analog systems that use continuous electrical signals, digital audio breaks your voice into thousands of tiny data packets. If even a small percentage of these packets go missing, or if they arrive in the wrong order, the system reverts to the dreaded “Silence.”
This guide is designed for the modern security technician. We won’t waste your time with “check if it’s plugged in.” We are diving into the packet-level reality of SIP audio. Whether you are dealing with a complex multi-tenant cloud setup or a local Peer-to-Peer residential installation, this guide provides the logic to solve every “No Audio” support ticket you will ever encounter.
2. Understanding the Audio Flow: The SIP & RTP Relationship
To fix audio, you must first understand that a “Call” is two separate conversations happening simultaneously across your network.
2.1 How Audio Works in SIP Calls (RTP Streams)
The SIP (Session Initiation Protocol) protocol is the manager. It handles ringing, answering, and hanging up. It uses UDP port 5060. Many technicians assume that if the call “rings,” the network is fine. This is a common misconception.
The RTP (Real-time Transport Protocol) is the worker. It carries the actual voice. It uses a dynamic range of ports (usually 10000 to 20000). RTP is independent. A SIP call can connect perfectly, but if the RTP packets are blocked, you have a silent, connected call.
3. Codec Issues: The Language Mismatch
A codec is essentially the math used to compress your physical voice into a digital packet. If the door station sends “PCMU” data but the monitor only knows “G.722,” the monitor will simply ignore the incoming audio packets because it doesn’t have the “key” to unlock them.
3.1 Supported Audio Codecs on Akuvox Devices
| Codec Type | Region/Use Case | Technical Characteristics |
|---|---|---|
| G.711u (PCMU) | North America / Japan | Excellent reliability, low compression, high compatibility. |
| G.711a (PCMA) | Australia / Europe | Essential for local installs. Matches Australian carrier standards. Ideal for residential alarm systems that integrate with intercoms. |
| G.722 | HD Audio environments | Crystal clear, but requires higher bandwidth and strict support. |
| G.729 | Weak 4G/Cellular links | Extreme compression. Can sound “robotic” due to low bitrate. |
| OPUS | SmartPlus Cloud App | The most modern codec. Dynamically adjusts to your signal strength. |
3.2 The Codec Negotiation Failure
When you setup a call, the device sends a list of codecs it likes. If the recipient responds with a list that has ZERO matches, the SIP call will often disconnect immediately or connect and give a “Codec Mismatch” error in the internal logs.
Indoor Monitors
Check the “Do Not Disturb” (DND) status. If it’s on, your screen won’t play any sound when the doorbell rings. This is a vital part of smart home security integration.
4. Network & Firewall Issues: Punching Through
90% of “One-Way Audio” cases are not caused by the Akuvox hardware itself, but by the client’s router incorrectly filtering the specialized voice traffic. This is a common issue we see when providing security system maintenance and support.
4.1 How Firewalls Block RTP
RTP packets are UDP packets. Unlike TCP (used for websites), UDP doesn’t “establish a connection.” It just starts shouting data at an IP address. Most firewalls see this as a “UDP Flood” and block the incoming data from the door station to protect the network.
4.3 Port Configuration Master List
If you are managing a commercial firewall (Cisco, Meraki, FortiGate), you must whitelist these specific paths:
- UDP 5060 – 5062: For Session Management and “Ringing” signals.
- UDP 10000 – 20000: For the actual Voice/Video RTP media stream.
- UDP 3478: For STUN server communication (essential for remote apps).
5. Microphone & Speaker Hardware: Physical Failure Points
If you have absolute silence and have verified the network settings, you must look at the hardware. Mechanical failures are rare with Akuvox but can occur in harsh environments.
5.2 Microphone Settings Deep Dive
Mic Gain: Controls the volume of the microphone. If the gain is too high (10), the device picks up so much “ambient noise” that the echo cancellation tries to suppress the entire signal, resulting in silence.
AEC (Acoustic Echo Cancellation): Digitally removes the sound of your own speakers from the mic input. If misconfigured, it can mistake your voice for an echo and mute it.
✅ Goldilocks Settings: Mic Gain: 7 | Speaker Volume: 7
6. SIP Configuration & Advanced Media Settings
For the advanced technician, these settings in the Phone > Audio or Phone > SIP page are the “secret weapons” to fixing persistent audio bugs.
6.1 Symmetric RTP: The “Punch-Through”
Enable Symmetric RTP. This setting forces the Akuvox unit to send its audio packets back to the exact same IP and port that it just received sound from. This effectively “punches” a hole in the firewall, allowing audio to return even if there isn’t a specific port forwarding rule in the router.
6.2 NAT Keep-Alive: Preventing the “Cut-Off”
Does your audio work for exactly 30 or 60 seconds and then suddenly cut to silence? Your router is “timing out” the UDP session because it thinks it’s inactive. Set NAT Keep-Alive to “Enabled” and the frequency to 20 seconds. This sends a tiny “heartbeat” packet to the router to keep the audio door wide open.
8. Firmware Updates: The Software Layer
Firmware is the brain of the intercom. Older versions often contain “VoIP bugs” that cause the audio stack to crash after a long period of uptime or during specific packet conflicts.
Recommendation: If your firmware is dated 2024 or earlier, update to the latest stable release. If the update fails or the unit becomes unresponsive, check our Firmware Recovery Guide.
10. Conclusion: Final Thoughts
Mastering Akuvox audio is about understanding the network logic:
- Silence is a language problem (Codecs).
- One-way audio is a directional problem (Firewalls).
- Choppy audio is a bandwidth problem (Jitter/Wi-Fi).
By following this guide, you have moved beyond “guessing” and into the realm of professional diagnostics. A properly configured Akuvox system provides years of crystal-clear security. Don’t settle for silence—fix the root cause and secure your property with the confidence only clear communication can provide.
Still Fighting the Silence?
Our Melbourne-based certified Akuvox technicians are ready to deploy. We resolve most of audio issues on the first visit with our advanced network analysis tools.
Sources and References
- Australian Communications and Media Authority (ACMA) – The official regulatory body for telecommunications and VoIP standards in Australia.
- Department of Infrastructure, Transport, Regional Development, Communications and the Arts – Government oversight on digital infrastructure and communication policy.
