The Bizfon 680 is a popular small business phone system. The Bizfon 680 was designed to be as simple as possible for users to set up and configure. The simplicity of the phone does come with some drawbacks, however. Many features that would otherwise be standard like multi-tenant configuration are absent from the Bizfon 680 to make it easy to program.
Voice Vault Cards
To address the shortcomings of their system, Bizfon released a set of add in cards for the Bizfon 680. These memory cards add additional 2 hours of voicemail greeting time or 4 hours. In addition, one card in particular can grant the multi-tenant capabilities missing from the Bizfon 680 originally.
These cards install in the top of your Bizfon 680. Under a panel you should see the slot where the Voice Vault flash cards are installed.
*CORRECTION UPDATE June 2015 - Thanks for your informative comments Cecilia!
This information is not correct. The Voice Vault card will increase your voicemail greeting time, not the amount of voicemails that can be stored on the system. It will still only hold 50 voicemails per control unit. It is installed in the slot on the side of the control unit. You unplug the unit, slide the card in, label side up, until only the Bizfon name can be read. Then plug the system in again. To use the extra time to make longer greetings, Bizfon must dial in to your system and adjust the timing. There are no screws to remove. The screw this article refers to is to hold the panel over the watch battery which controls the date and time on the system. If your system starts showing a date of Nov 1999 you must replace that battery.