Operating Systems

TERAVoice is supported on the following operating systems:

  • Windows 2000 Professional
  • Windows 2000 Server
  • Windows XP Professional
  • Windows Server 2003

The client tool is also supported on Windows 98 and Windows ME

Supported Telephony Hardware

TERAVoice supports both TAPI and CAPI based telephony hardware as well as voice modems and several CAPI based VoIP stacks.

Detailed Information about compatible brands and devices can be found on our Hardware Compatibility List. The following sections provide some general information about different types of hardware.


Basically any hardware is supported that is delivered with a TAPI-driver which supports audio playback and record. Some TERAVoice advanced features (e.g. call transfer) are dependent on appropriate hardware-support. If the driver does not implement a certain feature it won't be available with TERAVoice as well. Nevertheless not all kind of hardware is very well suited for operation with a telephony server system.


Especially European based telephony is usually built on CAPI. ( TERAVoice supports most CAPI 2.0 based hardware from n*BRI (S0, 2 lines) to n*PRI (E1 or T1, 24/30 lines).

CAPI based VoIP stacks

TERAVoice supports some CAPI based VoIP stacks which can be used to answer H.323 or SIP calls. The builtin support for H.323 in TERAVoice only supports bridging calls to H.323 terminals but does not allow to answer voice over IP calls for other tasks. This will change in a future version.

Voice Modems

While a voice-modem might be perfectly sufficient for small and simple voicemail configurations, several drawbacks exist: Audio-Quality and stability of audio communications is rather poor with some voice-modems. Voice modems often have difficulty in determining when a line is hung up, resulting in the line being blocked and messages recorded until the maximum recording time has been reached. Sometimes recognition of DTMF tones does not work correctly and call transfer is not supported for voice-modems, since the Unimodem driver does not support call-transfer.

PBX Support

TERAVoice does not necessarily need to be used in conjunction with a PBX system. For simple and small voicemail configurations or IVR-only configurations no PBX is needed at all.

Example 1: Voicemail for office with direct ISDN connection. An ISDN connection can have several MSNs (Multi Subscriber Number) assigned. Each MSN is dedicated to certain employee. TERAVoice voice mailboxes are selected dependent on MSN (= CalledID)

Example 2: IVR-solution on ISDN PRI with Scripts or ActiveX objects where no mailbox assignment is needed.

Basically all working combinations of telephony hardware and PBX systems can be used with TERAVoice. There are basically 3 features that are PBX-dependant:

Mailbox-Assignment: The telephony server is usually connected to certain PBX ports and assigned the appropriate extensions. When a user redirects his phone to the mailbox via explicit redirection (set on the phone) or implicit redirection (e.g. with ringing groups set in the PBX) the call gets signaled to the telephony server. There are several ways how the telephony server can get informed about the source of the redirection in order to know which mailbox to choose:

  • Inband signaling via DTMF tones: This method is commonly used with analog networks. A code of DTMF tones is signaled during the first 1 or 2 seconds after the call gets connected to the telephony server.TERAVoice provides full support for these method with configurable DTMF code patterns
  • Redirector information: In ISDN systems the number of the redirecting party is often transferred as ISDN redirector info. TERAVoice can use this info to select the corresponding mailbox
  • For PBX systems without redirector information or ISDN hardware connected to a public ISDN network that does not transmit redirector information, TERAVoice also offers MSN routing. The telephony must be assigned one additional MSN for each mailbox so that every user can redirect his phone to the corresponding MSN. The telephony server can select the corresponding mailbox depending on this MSN then
  • Additionally TERAVoice supports mailbox assignment depending on the hardware device. If you are using more than one device or your multi-line device can report several virtual devices, you can also use device-dependant mailbox-assignment

For each mailbox TERAVoice supports multiple entries of any combination of these options. This is extremely useful in a mixed environment with analog and digital telephony networks or different hardware.

Please note: Some PBX systems allow mailbox assignment with a custom protocol over a serial connection between server and PBX. TERAVoice does not currently support this option.

Messaging systems

The goal of unified messaging systems is to target all communications into a single inbox. TERAVoice does not require a special kind of messaging system and thus it is completely up to the customer to decide which system to choose or simply use TERAVoice with an existing messaging system.

Microsoft Exchange

Microsoft Exchange is one of the most wide spread corporate messaging systems all over the world. TERAVoice perfectly works in combination with MS Exchange 2000 or previous versions (with Internet Mail connector). One common procedure in combination with TERAVoice is the use of Public Folders' e-mail addresses as target for voice messages in order to allow collaborative access to new voice messages or use the call info message for creating log-files of calls.

Lotus Notes

Lotus Notes is similar to Exchange. By interfacing with the Lotus SMTP interfaces all TERAVoice messages are efficiently transferred to their recipients.

Other Messaging Systems

Nearly all concurrent messaging systems or mail servers are capable of transmitting internet e-mails via SMTP. Through its use of SMTP, TERAVoice is able to communicate with virtually any mail system.

A drawback exists for configurations that are using an external mail server system with low bandwidth internet connections. While these configurations are still possible, this setup is obviously not very efficient, since all voice messages would have to pass the internet network connection at least two times.


TERAVoice is one of the most flexible telephony server systems on the market. With its unprecedented support for TAPI and CAPI in a single product TERAVoice integrates into a broad range of environments.TERAVoice is one of the very few Telephony servers that offer a free version for download, so customers can be sure that the system will work within their hardware configuration and provides the desired features.

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