What Is a Spam Call, and How Do You Spot One?

What is a spam call

A spam call is a call you didn't ask for, sent not just to you but to many people at once. Its goal is almost always commercial or marketing: to sell, to advertise, to collect information through a survey, or to get you to call a certain number back.

Most of us know the word "spam" from email, where it means junk mail sent out in bulk. On the phone it's the same idea: not a personal call to you, but one call out of thousands, sent to everyone whose number is on the list.

What sets a spam call apart from an ordinary call from an unknown number is not the number itself, but the way it is sent. A new customer calling for the first time is an unknown number, but they are calling because they need you. A spam call calls you because your number was on a list.

An automated call with a recorded message is called a robocall. People also call it a "recorded call," an "automated message," or simply "another recording." And when a live agent calls to sell, that's called telemarketing.

Common types

Spam calls come in several forms. Most of them are familiar to anyone with a phone:

The last type calls for caution: some numbers, mostly overseas, are expensive to call back. If you don't recognize the number, it's better not to call it back.

The types often get mixed: a recorded message that offers to "press 1 to speak with an agent," or a survey that ends with an offer.

How an autodialer works

Most spam calls aren't dialed by hand. They come from an autodialer: a system that takes a long list of numbers and dials them on its own, many at once.

When someone answers, the dialer does one of two things: it plays a recorded message, or it connects the call to a free agent. To avoid wasting agents' time, some dialers call more numbers than there are agents, assuming most people won't answer. When more people answer than expected, there's no free agent, and whoever answered hears silence or a hang-up.

That's where the telltale sign comes from: a second or two of silence after you answer. That's how long it takes the dialer to notice you answered and connect an agent.

A dialer isn't a bad thing in itself. Organizations also use one to send appointment reminders, announce a change, or invite people who asked to hear from them to an event. What makes a call spam isn't the tool, but the fact that it's sent without anyone asking for it.

Signs it's a spam call

No single sign proves it, but several signs together say a lot:

• Silence at first. You answer, and only after a second or two does someone speak.
• A recording that starts right away. A voice that talks before you've said a word, and doesn't respond to what you say.
• A generic opener. No name and no context: "Hello, we have a special offer."
• Pressure to decide now. "Today only," "Press 1 now."
• Questions about personal details or payment details, on a call you weren't expecting.
• A number that calls everyone. Several people in the office get a call from the same number, one after another.

The last sign is hard to see from a single phone, but easy to see from above. That's exactly what spam filtering on the PBX checks.

Why you?

Many people feel that someone "sold" their number. Sometimes that's true, but usually the reason is simpler:

• Sequential dialing. A dialer can go through every number in a given range, one after another. It doesn't need to know who you are.
• A published number. A number that appears on a website, in an ad or in a phone book gets collected into lists.
• Lists that change hands. A number you once gave on a form can end up on other people's lists.

In an organization, this means that even direct numbers that were never published can get spam calls, if they fall within a range a dialer goes through.

A displayed number that isn't real

Some callers display a number that isn't theirs. This is called caller ID spoofing, and it's explained in the article on caller ID.

This has two consequences. First, the number on the screen doesn't always tell you who is really calling. Second, when you block such a number, you may also block the number's real owner, who did nothing wrong.

That's why systems that detect spam don't rely on the number alone. They also check how the number behaves and what is said on its calls, before blocking it permanently.

What spam costs an organization

One spam call is a small nuisance. Lots of them are a real problem:

• Staff time. Every such call interrupts work, even when you hang up right away.
• Busy lines. At peak times, a spam call can tie up a line or an agent in the queue while a real caller waits.
• Unwanted content. Recorded ads aren't always suitable for everyone's ears.
• Confusion. An employee who calls an unknown number back by mistake may waste time, and sometimes money too.

In an office that gets dozens of calls a day, even a few spam calls a day add up to hours of work each month.

What to do when you answer a spam call

A few simple rules every employee should know:

1. Don't press keys when a recording tells you to. Even "press 9 to be removed" sometimes confirms that the number is active.
2. Don't give out details on a call you weren't expecting, even if the caller sounds official.
3. Hang up politely and don't get drawn into a conversation.
4. Don't call back an unknown number that rang once and hung up.
5. Tell whoever is in charge of the phones, with the number and the time. That way the number can be blocked, or checked to see whether it's already blocked.

With a proper sales call center that has a live agent, you can simply ask: "Please take our number off your list." Most reputable call centers honor a request like that.

Spam or nuisance caller: two different problems

It's easy to mix the two up, but they are handled differently.

That's why there's no single tool for both. Against a nuisance caller, adding their number to a list is enough. Against spam, a list goes stale quickly, and you need a system that identifies the calls by what they do.

Spam in voicemail

When no one answers, a recorded spam message sometimes gets saved in voicemail, like any other message. If the voicemail box sends messages by email, it lands in your email too.

This is one more place where spam eats up time: someone has to listen to the message, realize there's nothing in it, and delete it. When spam is stopped before it reaches the extension, the voicemail box stays clean too.

What the law says

In Israel, the Communications Law (known as the "Spam Law") restricts sending advertising without prior consent. The restriction applies not only to text messages and emails, but also to advertising in calls from an automatic dialing system, meaning a recorded message played to whoever answers.

The law doesn't stop every call. Some calls come from abroad, some aren't advertising as the law defines it, and some simply don't follow the law. That's why filtering on your end is still needed.

And for those who use a dialer themselves: before a marketing campaign, check with someone who knows the law what is allowed and to whom. The article on dialers and dialing campaigns lists rules for good practice.

How to cut down on spam calls

You can't make spam disappear completely, but you can reduce it a lot:

• A short IVR menu up front. A message asking callers to press a digit to continue stops many automated calls. More on this in the article on IVR menus.
• Blocking a fixed number. A call center that always calls from the same number gets blocked on a list. See Caller Blocking.
• Detection by behavior. Against numbers that keep changing, spam filtering helps: it checks how the number behaves, not just what the number is.
• Don't publish direct numbers that don't need to be public.

It's the combination that works: each layer stops some of the calls, and whatever gets past one is stopped by another.

An example from the field

The nonprofit "Yad Avraham" (not its real name) has several direct numbers. One morning, a recorded message offering loans started coming in. It reached the number of David, the secretary, first; a few minutes later, the treasurer's number; and after that, everyone else's. Each day it came from a slightly different number.

Blocking one number didn't help, because the next day the same message came from a new number. What helped was a combination: a short message at the start of the main line asking callers to press 1 to continue, and joining the filtering service, which includes spam filtering.

When the next number dialed 10 different numbers on the PBX in a row, belonging to the nonprofit and to other customers, the service recognized the pattern and blocked it for an hour for all subscribers. The service manager checked the number, saw it was a recorded ad, and the block was made permanent. The office simply stopped getting these calls.