Commetrex’ OpenEndpoint provides the telephony software required to implement an IP endpoint voice-fax gateway. OpenEndpoint includes POTS interface software, signal generation-detection, packet voice, and T.38 and/or I.366.2 fax relay executing in Commetrex’ OpenMedia standards-based streams framework. All the OEM need add for a complete IP endpoint product is the signaling and application software. H.323 is optionally available. Although the software is available in portable-C format, a highly optimized version is available for the Texas Instruments TMS320C6000 family of high- performance DSPs. A single low-cost 200-MHz ‘C6000 provides, for example, 12 non- blocking channels running G.723.1.

The basic OpenEndpoint includes the POTS interface supporting both FXS and FXO interfaces, G.711 and G.726 voice coders, fax modems through V.17, T.38, caller ID transmit and detect, call classifier, and OpenMedia. G.723.1 and G.729a/b vocoders are optionally available, as is I.366.2 ATM fax relay.



License Options


OpenMedia conforms to the MSP Consortium, Inc. ( M.100 specification of a multi- stream integrated-media streams framework. OpenMedia can execute entirely on a DSP, entirely on a host or co- processor or partitioned across multiple processors. The latter system partitioning is often used in high-capacity systems where a blade includes multiple DSPs and one or more co-processors. This configuration permits all but a small-footprint execution controller to be partitioned onto non-DSP processors.

But OpenMedia is just as suitable to host-based signal processing. Commetrex uses it to implement OpenEndpoint with the MSP-H8 PCM interface PCI board.

POTS Software

IP endpoints that interface with either the PSTN or with legacy fax terminals or voice stations will have a PCM- and line-supervision interface for each analog line. These interfaces must translate call-control requests into the correct manipulations of hook status for outbound and ringing and loop-current status for inbound calls. The software includes a small executive that sequences the execution of state machines which implement each line- control function.

General Telephony

A system that supports analog lines must have the ability to generate and detect in-band tones, such as DTMF, monitor the state of outbound calls using call-progress analysis, and to classify calls to determine whether to apply voice, fax, or data-modem specific processing.

Voice Processing

OpenEndpoint includes the most popular vocoders and the voice-specific packet management needed to provide clear low-bandwidth voice. A G.168 echo canceller is included.

Fax Processing

OpenEndpoint includes Commetrex’ acclaimed PowerRelay, offering T.38 IP-based real-time fax in the based configuration; I.366.2 is optionally available for those systems using ATM. Both can be included for applications that must support both IP and ATM protocols.

Modem Data

The OpenEndpoint call classifier will determine whether a POTS call is voice, fax, or a data modem. Each requires media-specific processing for accurate transport. In 4Q 2002 the ITU has yet to determine the V.MoIP recommendation for modem relay. In the interim, OpenEndpoint switches to full-duplex G.711 (64-Kbits in each direction) for data-modem calls.

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