We're excited to announce a major improvement to SIP Caller’s Answering Machine Detection (AMD) algorithm. Until now, our system primarily relied on amplitude analysis—measuring the volume of sound—to determine if a call was answered by a person or a machine. While effective in many cases, this approach sometimes led to false positives, especially when a short beep or tone was misidentified as a brief spoken response.

What's New?

SIP Caller now takes a leap forward in accuracy by adding frequency analysis to the mix. With this new capability, our algorithm can distinguish between:

• Tones (like beeps or system prompts)
• Human speech
• Silence or background noise

This improvement allows us to correctly identify even tricky scenarios—like a voicemail greeting that starts with a beep instead of a voice, or ultra-short messages that used to confuse the old system.

✅ Before vs After Example

In the past:

• A short tone-only message might be identified as a human answer
• This triggered call transfer or message playback — wasting agent time and budget

Now:

• The system detects the tone’s frequency signature, confirms it’s not speech, and marks it as a machine

The Science Behind It

To make this possible, we’re applying advanced signal processing techniques, including:

• Fast Fourier Transform (FFT): Converts audio from the time domain to the frequency domain
• Peak frequency analysis: Human speech spans a wide range of frequencies, while tones show sharp peaks at specific frequencies

Below is an example of what the frequency analysis looks like:

A clear frequency spike indicates a tone (not human voice)

Human speech shows a more complex and spread-out frequency profile

Early Media Detection = Cost Savings

Another big win: We can now analyze early media, meaning we can often detect a machine before the call is answered.

Depending on your VoIP provider, this allows SIP Caller to:

• Drop the call before it's charged
• Skip non-human answers
• Save money—especially with high-volume campaigns

💡 If you're making thousands of calls daily, these improvements can lead to significant cost reductions.

Why It Matters

Accurate AMD means:

• Better agent efficiency
• Fewer wasted calls
• Lower phone bills
• More precise reporting

Try It Now

This new AMD system is already available for all SIP Caller users. No changes are needed—just run your campaigns as usual and enjoy better performance out of the box.

Want to see it in action or learn how it works with your current provider? Contact our team and we’ll be happy to help.

SIP Caller continues to push boundaries in call automation, bringing you smart, cost-effective, and powerful tools for modern communication.

Stay tuned for more updates!