June 28, 2026, 2:37 pm | Read time: 3 minutes
Sometimes the connection is poor, and you can’t hear the caller at first. But if the phone rings and there’s silence on the other end, it might be a so-called silent call. These silent calls often result from automated calling systems–and in some cases, they are part of planned fraud attempts. What you should know about the topic, at TECHBOOK.
A common explanation for silent calls is telephony dialers, often used in call centers. The Federal Network Agency provides more details on this. In this context, the software is intended to make workflows more efficient: It automatically dials phone numbers from a contact list, so employees don’t have to dial each number themselves or wait for a dial tone.
Some of these systems, known as predictive dialers, even dial multiple numbers simultaneously. If more people answer the call than there are available employees, it can happen that no one responds on the other end at first. Such a silent call is referred to as a silent call or lost call. This situation is annoying but fundamentally harmless.
When Silent Calls Pose a Threat
But it’s not just call centers that have recognized the practical use of automated calling systems. Such software is increasingly used to check on a large scale whether a phone number is active. It is also intended to help determine at what times a person can be reached at the called number, or if only a voicemail picks up.
The collected information can later be used for telemarketing calls, or worse: for fraud attempts. The verified phone numbers can also be traded in certain networks. They often serve as a basis for targeted phishing calls in various forms. The goal of such contacts is usually to obtain personal data (passwords, payment information) or directly get money.
How to Protect Yourself
Nowadays, most of us are aware not to answer calls from unknown numbers–especially from abroad–and not to call back. This is also the most effective protective measure against silent calls.
The tricky part is that with such automated calling systems, even a brief connection can be enough to confirm the phone number as active. This is pointed out by the cybersecurity firm Bitdefender. A conversation doesn’t even have to take place.
This distinguishes them from fraud attempts where criminals want to keep the called party on the line as long as possible. They intend to obtain personal information or, as occasionally reported, generate voice recordings to use for AI-based voice imitations. A strong recommendation is therefore not to speak and especially not to say “yes.” More information here.
As the Federal Network Agency further explains, some network operators offer their customers the option to block individual numbers or even entire blocks of numbers. Affected individuals can contact their phone provider directly to inquire about available blocking functions.