How Does MY Telco Know That YOU Have Dialed A Wrong Number?

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Callers are sometimes unable to reach me because

  • My phone is outside coverage area
  • I’ve switched off my phone
  • I’m busy
  • The network is congested.

Until this recently, whenever this happened, callers heard a message from my mobile network operator saying they’ve dialed the wrong number.

Naturally they wondered how the heck can MY mobile network operator know that THEY have dialed the wrong number when it has no way of knowing what the right number is!

I visited the store of my MNO – a leading UK-headquartered global telecom company with operations in India among many other countries in the world – to find a solution.

As soon as I complained about this pesky problem,  one of its agents would whip out their mobile phone and call my number. When their calls went through, they’d beam and proudly brag that the problem was “resolved now”.

They were neither able to understand that my problem was intermittent nor geared up to diagnosing a one-off problem. So, I gave up on trying to get any resolution from my MNO.

Life went on, I forgot about this problem since it happened infrequently.

This was until the beginning of this month. Due to network congestion, many subscribers of my MNO, including me, found our mobiles going off the grid several times a day. And, what was previously an intermittent problem became a regular feature.

I couldn’t ignore it any longer and decided to tackle the problem myself instead of going back to the MNO’s office and hearing the same old story that it was “resolved now”.

I did a little bit of testing with the many mobile phones in my household. When I called my mobile from another mobile and rejected the incoming call, I got the “you’ve dialed the wrong number” message. However, when I called another mobile and rejected the call, I heard a different message saying the subscriber was outside the coverage area or had switched off their mobile.

Hmmm. For the first time, it struck me that maybe the problem was specific to my connection.

I had my eureka moment very soon: The problem was with the voicemail settings I’d configured several years ago.

mnown9

When I lived in Germany and UK, voicemail was a part of the business culture in both countries. Therefore, when I bought my first mobile phone in India in 2003, I immediately configured the voicemail settings on the connection. However, voicemail never caught on in India and I’d completely forgotten about the feature very soon. However, the MNO had not: Whenever callers were unable to reach me, it dutifully diverted them to my voicemail box.

Through the years, the original MNO changed hands twice. Through these frenetic M&A activities, my current MNO jettisoned the voicemail box number (if not the feature itself). That’s why its diverts to my voicemail box hit a non-existing number, and it dutifully reported them as wrong number.

Once I cracked the root cause of the problem, the solution took no time. I disabled my original voicemail settings for all four scenarios under Settings > Call > Call Forwarding > Voice Call.

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All’s well that ends well but I’m not sure

  1. Why my MNO couldn’t come up with this solution when I visited its stores so many times over the years, or
  2. Why the succession of MNOs carried forward my VM settings for all these years but didn’t see it fit to carry forward the associated VM number.

If only these MNOs had jettisoned the voicemail settings along with the voicemail box number, I’d have been spared this years-long irritant.