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A Commetrex Corporation Whitepaper
Copyright© 2009
All Rights Reserved
The power and affordability of the PC, the increasing role of
communications in business and everyday life, and telecom
deregulation have led to the evolution of products that support the
economic development of telecommunications systems. Hardware
and software value-adding components allow the system developer to
skip the years and millions required to develop the bedrock
telecommunications technologies needed in telephony systems and
move directly to application development. This industry's structure,
although much less mature, is traveling the same evolutionary path
blazed by the PC industry, the most efficient value-creation industry of
all time.
These system-foundation products are improving along many dimensions, including the
support of additional media and switching capabilities. When the industry began in the
mid-‘80s, it only supported voice play-record. Fax send-receive was added in the late
‘80s. PCM switching came along in the early ‘90s. And the late ‘90s saw the addition of
IP telephony. Video is next. This increase in media diversity led to the serial
development of media-specific PC add-in boards and software.
However, dedicated-function resources led to high costs for systems that require
multiple media. Since MIPS pooling is not statistically effective in low-density systems,
there is an economic incentive for manufacturers to lower product costs by sizing the
DSP to meet the MIPS requirements of the particular media.
For example, an analog network interface and DSP-resource board that supports both
voice and fax will require the resources to simultaneously support four ports of fax, but
since fax requires roughly three times the MIPS of a voice-only resource. So the
integrated-media resource is only cost-effective for applications that require both media,
but over resourced for applications that only require voice.
However, the MIPS required to process specific media have remained constant, while
the MIPS available on host PCs, following Moore’s Law, have soared. Where the
required media-stream compute resource was once large compared with that available
on the PC, it’s trivial today. You can simultaneously receive 48 V.17 faxes on a typical
PC, and still have plenty of headroom. It’s now time to put those MIPS to work in
lowering the costs and increasing the system flexibility of low-density digital-media
telephony systems.
So, what if host MIPS, a very large resource pool, are used to process the media
stream? The hardware designer no longer has to be concerned about whether a stream
requires five MIPS for voice or 15 MIPS for a modem. As long as we’re not talking about
hundreds of simultaneous calls, the MIPS are there and they are essentially free.
Specialized hardware is then only required to provide the PCM interface, which is
necessary regardless of the media requirements if the network being supported is the
PSTN. Commetrex is now shipping its MSP-H8, a one-to-eight-line PCM interface.
Since all it has to do is get the media stream to and from the host, there’s little
component cost. The basic board is only $295. But much more than a PCM interface is
required to rival the functionality of legacy systems.
The supporting software architecture, Open Telecommunications Framework®, is
radically different from the classical PC-based telephony platform. In the last-generation
architecture, buffers of fax-image or voice-file data are transferred to and from an add-in
board, which has a complex embedded software framework to support the DSPs and
their algorithms. But with the MSP-H8, the stream-processing environment is moved to
the host PC. This streams environment, a separate licensed product, is called
OpenMedia™. The results of the stream processing (for outbound data) are PCM
buffers, which are transferred to the board. The board feeds OpenMedia PCM buffers
for inbound data. And since the stream processing is performed on the PC, it’s easy to
validate new stream-processing software, even if it is destined for an embedded
application.
Commetrex sells its MSP-H8 as a hardware-only product for those developing their own
stream-processing software. An MSP-H8 Board-Level SDK is available for the
embedded developer. For the host-application developer, Commetrex offers developer’s
kits for its S.100-conforming OTF Kernel™ middleware. This a la carte licensing means
the developer pays for only what is required, and no more.
MSP-H8 Embedded SDK
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