Prosody S
is a software only product providing core speech processing resources that run on a host PC’s CPU – eliminating the need for a dedicated digital signal processing (DSP) resource card. Prosody S operates in a voice over IP environment and is accessed via Aculab’s generic API.

Why host processing?
Traditionally, media processing functions have been accomplished using dedicated DSP resources on a card located in a PC expansion slot. This approach benefits from having a well defined set of performance characteristics.

It has the advantage of being highly scalable if the cards are well designed and minimise the interactions with the host processor and the host is left alone to execute the application program. The only drawback of this approach has been a high entry cost for small-scale solutions.

For up to 120 channels of IP telephony, the power of today’s host processors makes it feasible to run all the necessary speech processing functions on the same server as the host application. Prosody S has been specifically engineered such that the traditional problems sometimes associated with IP telephony – such as drop-outs and delays – are minimised when used in IVR-type applications.

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Faster time to market
Prosody S is also available as a media processing resource for use with the Envox 6.1 Communications Development Platform and VBVoice, the Rapid Application Development environment product from Pronexus. Prototyping of your product can be very fast indeed using these application generation platforms, rather than the lower level coding that would otherwise be employed.

Feature support

Prosody S supports a number of speech processing features in common with the Prosody DSP resource card, including:

  • G.711 playback and record in either A-law or µ-law

  • Silence detection and elimination for recording

  • DTMF generation and detection

  • Simple tone handling with user defined tones

  • Automatic gain control (playback and record)

  • Volume control (playback and record)

  • Support for Aculab ASR and TTS

  • Optimised two-party conferencing, which can be used to mix the inputs from two separate parties and record them to a single file

    IP media session software is proven technology with our IP telephony hardware and is included with Prosody S. Features include:

  • SIP and H.323 protocol support

  • Adaptive jitter buffer

  • RTP

  • DTMF over IP packets – RFC 2833 for SIP and via User Indication for H.323

  • Voice activity detection and discontinuous transmission (DTX)

  • Record termination on silence

  • Two IP calls may be switched together (‘tromboned’) using the Media Point API, while A-law and µ-law coding conversions are performed if necessary between the two calls

    Additional Prosody S features:

  • On a typical current specification machine 120 IP channels are supported with the following speech processing:
    - 60 conference and 60 record channels
    - 120 half-duplex play and record channels

  • Aculab installation and configuration utilities (AIT/ACT) available when using Version 6 telephony software or later

  • Support for Windows XP/2000/Server 2003 operating systems

  • Prosody S can co-exist with Prosody cards in the same server, allowing an application to separately handle calls in both IP and TDM environments.

  • Prosody S is not dependent upon proprietary processor features and is suitable for use with AMD and Intel devices

    New features will be added on a regular basis to address opportunities identified with our customers. For your additional requirements please contact your Account Manager.

    Supply and support
    Prosody S is available to purchase under a software licence agreement via your Account Manager - when purchasing licences you have the option of ordering Prosody S software on a CD or downloading it via the Aculab installation tool (AIT).

    Aculab consider support a key part of the product and as such our technical support services are included in the price – unlike most competitive offerings.


Tel: 603-524-2214
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