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Welcome to the online training series from 3CX. This module will concentrate on the Voicemail functionality of 3CX.


The voicemail functionality is so ubiquitous with a PBX, that a lot of people take it for granted. Especially if it is available for free, with every edition of 3CX. However, there are multiple voicemail capabilities which are really handy, and we will see each one of the capabilities listed here. We will finish the module with the security of the voicemail as well as some tips for backing up the voicemails of the users.


Unlike other vendors, where voicemail is an added feature, 3CX provides a voicemail box for each of the extensions in the PBX, across all editions and irrespective of the size of license.

A voicemail box can have a different language than the default system prompt language, allowing you to have a truly multilingual PBX, where each extension can have a different prompt language. This requires the relevant prompt sets to be downloaded to the PBX.

The Voicemail System can be configured to make outgoing calls from the PBX. This can be used by extension users who do not have a smartphone to install the 3CX client, or do not have a data connection available due to remoteness or even running out of data. All you need to do is point a DID to the main voicemail extension. This will then prompt callers for an extension number and voicemail PIN number. Once authenticated, the caller will need to go into the options of the voicemail, by pressing 9, and then choosing option number 3.

From within the voicemail options it is also possible to change the profile state as well. This would be option number 1. All the caller needs to do, is follow the prompts.


When you receive a voicemail, there are various ways to get notified of an incoming voicemail. The most traditional way is to see the Message Waiting Indicator on the phones. A flashing light is always a good way to get someone's attention, but not all phones will flash. Some just light up the indicator and keep it on. This will differ between makes and models of phones.

In addition to the Message Waiting Indicator, 3CX is in a position to also send an email notification to the extensions user. This could only contain the notification, but it may also contain the voicemail as an attached WAV file. There is also the option of deleting the voicemail file from the PBX after sending it as an email attachment.

With the 3CX clients and web client, it is possible to also see the list of voicemails received in one easy to read interface. From these interfaces it is also possible to manage the voicemails, which allows you to mark them as heard or unheard and even delete them from the PBX, assuming the email sending notification option is not set to delete them.


While there is a default greeting for each of the available languages configured on the voicemail of the extensions, it is possible to customise this and record your own prompt.

A lot of companies may have their own professionally recorded prompts added to the voicemail system as a greeting prompt, or record one directly from one of the provisioned phones. This will allow for a more personalised greeting and can make the person more comfortable when they hear a familiar voice, rather than a generic prompt voice.

When a greeting is recorded, you can assign it to either all of the extension profiles, or have a different greeting for each of the 5 different profiles available for an extension. The extension profiles are covered in more detail, in the Forwarding Rules module.


When a voicemail is received, sometimes it can be short and precise and just a few seconds long. However, some can get quite long winded and this will take up alot of the perons time to go through all the voicemails which have been left, especially when the user has been away for an extended period of time.

It's now easy to sift through the voicemails using the voicemail transcription functionality.

Using a 3rd party API, namely Microsoft’s Bing Speech API, we are able to have a transcript of the WAV file. This provides an easy way of seeing the content of each of the voicemail messages, through the email notification and the 3CX Web client. This way you wont need to listen to each and every message to see which are the important ones.

Voicemail transcription requires a Professional or Enterprise Edition 3CX license to be active on the PBX, and it is a feature which is enabled globally for all extensions.

Some configuration is necessary on the Microsoft Azure Platform as well as the PBX in the form of creating an API key on the Microsoft platform, and copying this over to 3CX, in order to allow proper communication between the two.


Being WAV files, the voicemail files can take up a significant amount of space on the server hard drive.

A quota for voicemail usage can be assigned in order to limit the amount of disk space is used by the voicemail files. When the quota is assigned, the admin will want to be notified when the quota is nearings its use. An email can be sent to the admin when the quota is nearing its full use and the percentage of quota can be configured to trigger the sending of the email.

Sometimes people listen to their voicemails but never delete the old ones. If you don't have them being deleted from the server immediately after being sent to the user via email, you can configure the server to delete old voicemails older than a specified number of days.


Security is something which is on everybody's mind these days and the voicemail functionality can be secured to make sure it isn't used as a way into the PBX.

When voicemail is not needed, it should be disabled on certain extensions. This could include phones in common use areas, like reception areas, kitchens, etc. This will prevent people from using functionalities within the voicemail system, like dialling external calls.

Authentication to the voicemail system can also be disabled in some cases, where you will just need to call the voicemail extension to receive messages from the phones provisioned on the specific extension, without entering a PIN number. Calling to the voicemail system from another extension, or from outside, via a DID will still require authentication with the PIN Number.

If you are in a secured environment, like a hotel room, where not everyone has access, voicemail authentication is not required.

When PIN authentication is required, there is a hard coded limit to how many times a PIN number can be entered incorrectly. This is set to 3 failed attempts, after which access to the voicemail system will be blocked for a period of 2 minutes.

PIN Numbers by default are 4 digit numerals but can be increased to 10 digits for increased security.

The ability to make outgoing calls from the Voicemail menu is disabled by default and will need to be specifically enabled to allow this functionality to work.


Back ups are very important to the proper functioning of any system, and provide peace of mind to any admin.

The backups of 3CX are so easy to perform that there is absolutely no excuse for not having a backup of your PBX.The voicemail files are not backed up by default, so you will need to specifically choose the “Voicemails” option in the Backup and Restore page in order to backup the voicemail WAV files.

As the WAV files will take up a significant amount of space in the backup file, you can choose the email option to send the WAV file as an attachment in the voicemail notification, and then to delete it off the server. This will basically offload the WAV file to the email server and email clients, keeping the backup file size smaller than what it would be, when this option is selected.

[SLIDE 10]

Thank you for following this online training course. Follow our online webinars for demonstrations on the modules covered in our online training course. See you at another one of our online training

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