ASC and SPIRIT first Linux based voice logging system

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ASC and SPIRIT first Linux based voice logging system

With open-source Linux telecom solutions such as Asterisk and Pingtel gaining steam, it's always good to hear about another Linux telecom solution.

While this one is not open-source, it is important in that it is the world's first Linux-based call recording system.

here's the news:
October 5, 2004 - ASC ( offers world's first Linux based voice logging system based on SPIRIT ( speech compression software providing toll quality even in narrowband channels.

For what purposes do people record speech? Usually, to be able to listen to the records later to recover important pieces of data gone unnoticed initially. That's why speech quality is extremely important for communication logging systems. At the same time compression rate (higher compression leads to lower speech quality) is one of the crucial selling points for communication loggers. The good news is that ASC designed a logging system providing toll speech quality at low bit rate.

Having more than 40 years of experience and recording thousands of hours of speech, ASC is focused on recorded speech quality. That's why ASC chose SPIRIT software as the base for its new voice logging system.

Thinking about desired compression rate, speech quality and available processing power SPIRIT experts advised ASC to choose SPIRIT proprietary 4800 bps vocoder based on well-known CELP model and strongly optimized, providing nearly toll speech quality (MOS about 3.7) at low computational complexity.

Since ASC provides a Linux based voice logger, a decoder that runs with Linux as well as with Windows was required. SPIRIT 4800 bps vocoder was divided into DSP-based encoder and OS-independent PC-based decoder. This allowed ASC to get a speech codec targeted at their specifics and satisfying all their technical requirements (speech compression < 8 kbps and quality MOS >= 3)

SPIRIT solution ensures desired speech quality that is extremely important for logger as well as design flexibility and ability for system upgrades without considerable effort. So without wasting additional time and money ASC could make its business more effective and user-friendly. "You can't argue flexibility is a very useful feature. Imagine you have a running system and would like to make it more effective. With SPIRIT software embedded you don't need to buy a new system as we can just update the current version." - says ASC's Volkmar Henkel, Director New Technologies.

"Combination of toll speech quality and low bit rate is a real challenge, but ASC perfectly coped with this providing world's first Linux-based voice logging system for narrowband channels" - comments Andrew Sviridenko, founding CEO of SPIRIT.

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