VOCAL offers a comprehensive and fully optimized facsimile software library for a wide variety of platforms. V.21 channel 2 and V.27ter are the minimum requirements for Group 3 Fax. For non-V.34fax, V.21 channel 2 is used to transfer T.30 control frames. The “high speed” modulations, V.27ter, V.29 and V.17, are used for the “compressed image” transfer. The term “compressed image” refers to high speed data which may in actuality be other data, such as in the case of binary file transfer (BFT). As an option, these modulations can be combined with VOCAL’s V.34fax to provide image transfer rates of up to 33,600 bps.
All of the facsimile modulations and data streams can be controlled with VOCAL’s T.30 functions or with VOCAL’s facsimile service class 1 command sets (EIA-578 and T.31). The T.30 functions could in turn be controlled with VOCAL’s facsimile service class 2 command sets such as T.32 (known as fax class 2.1), EIA-592 (known as fax class 2.0) and industry standard (known as fax class 2). Typical systems can be configured to use T.30 Error Correction Mode (ECM), T.4 copy quality checking/corrections and perform image form conversion for T.4/T.6 and JBIG.
The line interface may be an analog front end (codec and DAA) or a digital interface such as T1/E1, xDSL, ATM, and ISDN. The application interface of this software can support a fax class 2/2.0/2.1 command set or may be used directly by an application.
VOCAL's embedded software libraries include a complete range of ETSI / ITU / IEEE compliant algorithms, in addition to many other standard and proprietary algorithms. Our software is optimized for execution on ANSI C and leading DSP architectures (TI, ADI, AMD, ARM, MIPS, CEVA, LSI Logic ZSP, etc.). These libraries are modular and can be executed as a single task under a variety of operating systems or standalone with its own microkernel.
Facsimile features available for support of the following features on a per channel basis:
The base RAS modem supports the following features on a per channel basis:
The signal detectors are useful for determining the progress of a call by audio means, obtaining user pressed DTMF digits and mode transitioning. The signal detectors include:
The system provides a wide variety of per-channel frame statistics that are updated continuously during operation. The statistics are accessible by the driving application and can be used for system monitoring and network bandwidth management. The statistics include: