VOCAL’s facsimile/fax lawful interception software library provides fax demodulation software for image extraction and decoding from intercepted PSTN audio signals. It allows interception, monitoring, and analysis of both Super Group 3 (V.34) Fax and low speed (V.17) fax communications from previously recorded input files or real-time sources. The facsimile intercept module has been deployed in surveillance equipment worldwide to assist law enforcement officials and government institutions.
- Extract and decompress page data to viewable image files
- Partial page recovery for damaged and partial recordings
- Processes real-time continuous stream and pre-recorded data
- Automatically classifies traffic by type, including voice, data, facsimile and non-standard or custom types
- Automatically classifies FAX traffic by modulation and non-standard or custom types
- Supports both V.34 FAX and low speed FAX (V.17, V.29, V.27ter, V.21 Channel 2)
- Supports T.30 Group 3 Facsimile Timing and Control Procedure
- Supports T.30 Error Correction Mode (ECM)
- Supports T.4 One and two dimensional (MH and MR) image decoding procedures
- Supports T.6 MMR Image Format Conversion
- The fax image decoder can operate at multiple sample rates, including 16 KHz, in order to ensure the highest input signal quality.
- The facsimile monitoring module for PSTN lines includes fax image decoding for both standard facsimile as well as machines that make use of manufacturer specific T.30 ‘Non-Standard Facilities’ (NSF) features.
- For recorded files using low-speed demodulation, an auto-detect mode that does not rely on FSK frames is also available. This allows for fax demodulation using NSF negotiation or where control data may not be readily available.
- The fax image decoder ensures accurate image recovery through the use of blind data retrieval and consistency checks, thus avoiding possible compatibility issues with non-standard facsimile machines.
- The output file format of the fax image will be either TIFF or standard Microsoft bitmap format (bmp), and can be selected for a specific implementation.
- ANSI C, Assembly, Binary or Source
Block Diagram of the VOCAL’s fax interception software provides fax demodulation for image extraction and decoding