Wireless Block Identifier® - Easy Identification of Cell Phone Numbers

There is no cell phone do not call list for telemarketers and collectors to work from. Still, Federal Regulations restrict organizations when making unsolicited marketing and collection calls to wireless numbers. Can you identify the cell phone numbers on your list?

For an accurate identification of cell phone numbers, you must use the Wireless Block Identifier® File and the Wireless Ported Number File together.  IMS has been providing wireless identification products and services to Direct Marketers, Collection Agencies, Attorneys, and Telemarketers since 2002.

The Wireless Block Identifier® file identifies those Area codes and Exchanges or blocks of numbers assigned to wireless carriers active within the North American Numbering Plan in the U.S. and Canada. An updated file is made available twice monthly for download and covers over 650,000 blocks representing some 650 million plus phone numbers that are currently assigned or will be assigned to mobile phones.

Each record on the file contains 5 fields labeled:

The first three fields contain a total of 7 digits that identifies a block of 1,000 telephone numbers assigned to a wireless carrier. These 7 digits, representing the area code, exchange and 1st position of the telephone number, must be matched to the first 7 digits of the prospects telephone number. A match indicates that the telephone number has been assigned to a wireless carrier.

A replacement Wireless Block Identification® file is created twice a month, zipped and placed on the web site about the 10th and 24th of each month. When the new file is posted, a notifying email is sent to all subscribers.

The available WBIaudit file is not intended for day-to-day use and may be used to reconstruct a wireless block file for any point in time since 2010.

Also available to wireless block subscribers is our on-line lookup of telephone numbers to assist subscribers who occasionally need to know if single numbers are either wireless or landline.

How to use the Wireless Files

Wireless Block Identifier® Frequently Asked Questions


The price for a 12 month subscription to the Wireless Block Identifier® file is:

 A single fine for illegally contacting a cell phone number is $11,000 according to the Telephone Consumer Protection Act.

How to subscribe to the Wireless Block Identifier® File:

Learn more about the Wireless Ported Numbers File which allows for the identification of numbers that have been assigned to landline carriers but have been ported (switched) to wireless carriers and visa-versa. To correctly identify a cell number, both the Wireless Ported Number and the Wireless Block Identifier® files should be used together.