Business Support

Important Notification for Businesses Using Multi-line Telephone Systems

ATMC has had reports of recent fraudulent activities in our area that could affect your business. If you use a multi-line telephone system or PBX with voicemail you could be susceptible to long distance call hacking that could cause you to incur thousands of dollars of unauthorized long distance charges. Please read carefully for more information.

It is imperative that you protect yourself by ensuring that your employees change their default passwords to unique number combinations that may not be easily guessed. As a customer with a multi-line telephone and voicemail system, you are responsible for the protection of your equipment and any toll charges made on your account.

If you have general questions about protecting your business communications equipment, we recommend that you contact your business communications equipment provider. If your business communication equipment was installed by ATMC, call 755-1675.

If you suspect you have been a target of criminal activity, it is your responsibility to contact the local authorities immediately. ATMC will cooperate in every way with any criminal investigation.


For more information on how to protect your business, check out the tips below:

General practices for protecting your multi-line telephone system:

  • Require your employees to change the default password on their voice mailbox as soon as it is assigned to them. THIS IS EXTREMELY IMPORTANT.
  • Program your voicemail system to require passwords with a minimum of 6 characters (8 character passwords are preferred). The more complex your password, the more difficult it will be to hack.
  • Train employees to use passwords that are not easily deciphered. Examples of low security passwords are: the telephone number, the extension number, or simple number combinations such as 1234, 1111, or any repeated number.
  • When assigning a telephone to a new employee, never make the temporary password the employee’s extension number. Make it unique. This makes it more difficult for hackers to guess.
  • Program your voicemail system to force users to change their password at least every 90 days.
  • Certain features allow long distance calls to be made through a voicemail system (specifically the end user’s mailbox) from an offsite location. Determine whether you need this feature activated. If you don’t, have it disabled. This disables a hacker’s ability to make outbound calls by infiltrating unguarded voice mailboxes.
  • Never have unassigned voice mailboxes on the system. When someone leaves your employment, remove old messages and delete their voice mailbox immediately.
  • Restrict the Voicemail Remote Notification option to only contact approved pagers or mobile phones.
  • Consider placing restrictions on international dialing or have dialing filters which allow or restrict calls to specific countries.

The above security measures are general in nature and may not protect every multi-line telephone system. We encourage you to contact your equipment support provider to discuss the unique aspects and vulnerabilities of your specific multi-line telephone system in greater detail as soon as possible.


Each business should assign a system administrator to manage your multi-line telephone system and assist employees with basic phone system tasks and maintenance duties, such as: resetting voicemail passwords, adding and deleting voice mailboxes, and enabling and disabling telephone features. You are responsible for all calls made from your multi-line telephone system.

What should you look for to determine if you are a victim of toll fraud?

Review your monthly telephone statement for abnormal calling patterns such as: calls to unusual locations, high call volume, long call durations, international calls and calls to 809 or 900 area codes and high traffic after business hours.

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