Direct-Dial Directories: How to Research Staff via Phone Numbers

Mar 31, 2009
This article is part of a series called Tips & Tricks.

A valued customer asked me to ferret out 1,000 names and numbers from a satellite office of a large company (22,000 employees total). I’ve done this work for him before — I’m not sure but I suspect he uses the work for sales development, the theory being that these people all have well-paying jobs in one of the more healthy sectors of our economy.  He has ordered many of these custom-developed directories from me before, so whatever madness is behind his methodology it seems to work for him! This is how it’s done.

Discover a Company’s Phone Number Prefixes

A telephone number’s prefix is the first three numbers after the area code. Often, the phone number for a company’s receptionist will have a different prefix than that of the direct-to-employee phone numbers. For instance, the receptionist might be 703-123-4567 whereas the employee numbers begin with 703-934-xxxx or 703-434-xxxx.

To discover the various prefixes, place the company name and area code in a Google search box and hit “enter.” If you’re lucky, you will come up with more than the main number as employees are often listed in various places with their direct lines.

I was recently researching the phone banks of a company that only used one prefix — the same one for the main number and employees. When this happens, it’s a good bet the “direct dials” are going to lie somewhere “around” the main number. For instance: The main number is 703 456 2000. Dialing 703 456 2001 and then 2002 and then 2003 will, many times, reveal employees seated behind those numbers. Pretty cool, huh?

I could tell looking at the Googled results that the numbers appeared to fall in the 5000, 6000, 7000, and 8000 ranges even though the main number fell in the 6000 range. This told me that I was probably dealing with a location that held 2-3,000 employees.

Call After Hours

The next thing you want to do is dial through a long list of consecutive numbers around the numbers you have found. The goal is to get the name associated with each number.

If someone answers, usually they don’t reveal their names. The best time to get the name is to call after hours and on the weekends when you are more likely to get voicemails.

Program Your Phone to Dial Repeated Numbers Automatically

When I am dialing through a long list of phone numbers that all begin with the same seven digits, I program these first seven numbers into my telephone to allow me to dial them by pressing one button.

What Voicemail Reveals

A few voicemails will contain not only a name but other information as well.

“This is Sheila Jones. I’ve begun my retirement but if you have issues with the WolfCamp project call so-and-so at the site at xxx xxx xxxx or so-and-so here at the main office. Her number is.”

“Hi. This is Mike Peterson. I’m traveling overseas on business and will be back in the office on March 31. The best way to reach me is my email — send me an e-mail at and I’ll get right back to you.”

“Marcus Meters here, HR Manager for the southwest. I’m out of the office until April 6, but if your matter is urgent contact Sandra Morelli at xxx xxx xxxx or Elizabeth Southland at xxx xxx xxxx or Fred Kloppers at xxx xxx xxxx.” Man, is that the whole HR department, or are there more?

“Jim Delaney’s office. If you need to schedule some of his time, contact me, Rachel Evans, at xxx xxx xxxx.”

“I rarely check this location’s voice mail. To reach me, call my cell at xxx xxx xxxx. I’ll get right back to you.” (Oh, by the way, calling the cell number revealed the guy’s name!)

These tiny bits of information give you a feel for what’s going on inside a company. For instance, I found that all those people Marcus counted off fell within 10 numbers of his number. This is a pretty good clue that people who worked in the same departments shared extensions close to each other. This makes it easier to identify people with specific skill sets inside the organization.

Jim Delaney is important enough to have someone answering his phone and scheduling his time, so this is a pretty good indicator he is in upper management or maybe even a C level. Checking an information source like Hoover’s sometimes will reveal that (and the correct spelling of his name!)

By the way, Rachel sat three numbers away on the extension tree so this bolstered my suspicion that whole groups mostly hung together in the phone directory.

Mike Peterson was so gracious as to reveal the company’s email domain and that is of interest many times to the customer. He also told us his job includes oversees travel and is a hint that maybe he is engaged in project management? Sales? Business Development? Could be anything but those come first to my mind.

Cell numbers left on a voicemail often indicate that a person is working in a sales capacity.

If this kind of work is too time-consuming and monotonous for you, there are people out there who are dying to do this work for you. For about a buck a name you can capture a particular company’s telephone directory that includes names, direct-dials, a few titles, and some information that gives you an insider’s feel for a particular company’s location. Imagine what you could do with all that!

This article is part of a series called Tips & Tricks.
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