Currently, CopiaFacts can both send and receive color faxes, but several other planned facilities are not yet released. In the following descriptions, only the currently available capabilities are described.
Color Faxing is an extra-cost option for CopiaFacts. It is not yet supported in the CFHWL license manager. In the interim, instructions will be provided to enable color fax operations by means of a configuration file setting. The color features described below will not work successfully without this setting.
Color is supported only on Brooktrout TR1034 boards, either with API release 5.2 or later. Color is not supported in the CopiaFacts interface for any earlier Brooktrout release. Color support requires CopiaFacts engine 7.191 or later.
To enable color receive on the TR1034, use the Brooktrout ConfigTool program and set the checkboxes for JPEG and Full Color (scroll down in the Advanced settings for BTCall parameters). No other enhanced fax format (EFF) options are supported. The ConfigTool program modifies BTCALL.CFG to add support for color receive.
If the BTCALL.CFG file specifies that color receive is allowed, all channels will advertise this capability to incoming calls. If color faxing is not enabled in CopiaFacts, the receive will not be set up for correctly color and the data will be saved in a .TIF file. The .TIF will not contain valid data and will not be viewable either as a TIF or as a JPEG.
When correctly configured, CopiaFacts will recognize an incoming color file automatically and save it in an infopacket (.IPK) file. This file is a Brooktrout-specific file containing identifying headers followed by data blocks. Each received page will consist of a JPEG format file embedded (in multiple pieces) in the IPK file.
The color fax JPEG format is different from that commonly used for .JPG/.JPEG files in web pages and digital cameras. The files are in general incompatible and files produced by color fax machines cannot be viewed or processed in the vast majority of image editors, viewers and browsers which support JPEG formats.
Color fax JPEG files conform to the ITU T.42 specification. The principal differences from more familiar JPEG files used almost everywhere else are:
•The file has a special G3FAX header, not the more common JFIF header.
•The image height is stored at the end of the file, not in the frame headers (because it is usually not known until after the file transmission has started).
•The image height is identified by a special 'DNL' marker which is either rejected or not supported by standard JPEG processors.
•The color space of the image is a special version of CieLAB with the normal L*A*B* parameters constrained to specific ranges. This is not recognized by readers expecting only JFIF standard files and results in a display with incorrect colors.
The received filename (.IPK for color or .TIF for monochrome) is placed in the MCF as usual and is also available in the PR_FAXFILE and PR_FAXPATH system variables. There is also a PR_FAXFORMATvariable which will contain the CopiaFacts image-type code of the received file, 93 for IPK and 59 for TIF.
The CFCOLOR program can used to extract JPEG files from a received IPK file named on its command line, either in the T.42-compliant format in which they will have been transmitted, or converted to normal JFIF JPEG files or color TIF files. Since JPEG files use 'lossy' compression, and the file needs to be uncompressed to convert color space, then recompressed, it is advisable to keep the number of JPEG compression operations to a minimum in order to preserve image quality.
A color file to be transmitted by CopiaFacts is named in the normal way on a $fax_filename command. Only one $fax_filename command can be used in the FS file for a color transmission. A single page transmission may be specified either as a .JPG (the extension .JPEG is also valid) or a .IPK file; for a multiple page transmission the specified file must be an .IPK file.
If you attempt to transmit a color fax to a remote machine without color capability it will normally fail. But when CopiaFacts prepares the transmission, if a file is found with the same path and basename as the file specified for transmission (JPEG or IPK) but with .TIF extension, then it will be treated as a 'fallback TIF file' and CopiaFacts will attempt to transmit it if the remote machine does not advertise color capability. If the 'fax local copy' option is enabled, the fallback TIF must be placed in the local folder; it is not automatically moved there.
The CFCOLOR program can be used to convert in various ways between T.42-conforming JPEG files, regular JFIF JPEG files, Brooktrout IPK files, color TIF files such as those produced by ImageMaker's color print driver, and also regular monochrome faxable TIF files. The last can be used to create a 'fallback TIF' file. It is important to ensure that files to be faxed in color have 200dpi horizontal and vertical resolution, and an image width of exactly 1728 pixels. Files of other formats may not fax successfully to color fax machines, and will not produce a faxable file if converted to monochrome using CFCOLOR.
If you attempt to transmit a regular JFIF JPEG file instead of a T.42-compliant JPEG file, it will be rejected by CopiaFacts and not presented to the fax board. Unlike a monochrome fax file, the fax board has no knowledge of the file format, and all JPEG files are theoretically 'faxable' when a board such as the Brooktrout TR1034 is used at both ends of the connection. However only those JPEG files conforming to T.42 will be sent by, and correctly received at, a real paper based color fax machine.
Brooktrout do not support a fax header line for color faxes, so any $fax_header command will be ignored. The command will be used, however, to transmit the fallback TIF if needed.
Color faxes are not yet specifically identified in the DBF log file. The CopiaFacts console display does not update with a page number as each page is processed. If any connect time, call time, baud rate or other data is recorded for a transmitted or received color fax, it may not be correct.