CID to FAX Converter

Render CID font glyphs as fax-compatible bitmap images online

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Fax-Ready Output

Produce CID-keyed CJK character images in standard fax encoding — ready for direct transmission via fax software or machines.

Rapid Processing

Monochrome fax rendering from CID fonts completes in seconds. Get your fax-compatible glyph images without delay.

Entirely Browser-Based

No fax software or font tools needed locally. Handle the entire CID to FAX conversion through your web browser.

How to convert CID to FAX

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose fax or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your fax file right afterwards

About formats

CID (Character Identifier) is a font architecture developed by Adobe Systems and specified in June 1993 to address the challenges of fonts containing very large glyph sets, particularly for CJK (Chinese, Japanese, Korean) scripts. Traditional PostScript fonts identify glyphs by name, which becomes impractical when a font contains tens of thousands of characters — a typical Japanese font may include over 20,000 glyphs. CID-keyed fonts replace glyph names with numeric identifiers organized by a character collection and ordering (such as Adobe-Japan1 or Adobe-GB1), dramatically reducing overhead for glyph access and subsetting. The architecture defines three PostScript font types: Type 9 (CID-keyed Type 1 outlines), Type 10 (CID-keyed Type 3), and Type 11 (CID-keyed Type 42/TrueType). A primary advantage is efficient handling of massive character sets — the numeric CID approach eliminates the memory and processing cost of maintaining thousands of glyph name strings. CID fonts also support sophisticated CMap resources that map encoding values to CIDs, enabling a single font to serve multiple encoding schemes (Unicode, Shift-JIS, Big5) without duplicating glyph data. The architecture integrates well with PDF subsetting, allowing documents to embed only the glyphs actually used. CID-keyed technology laid the foundation for CJK support in both OpenType and modern PDF workflows, and remains active in print production and document processing systems worldwide.
Developer: Adobe Systems
Initial release: June 11, 1993
FAX is a generic image file extension associated with facsimile transmission formats standardized by the ITU-T (formerly CCITT), with the underlying Group 3 compression standard ratified in 1980. FAX files typically contain monochrome (1-bit, black and white) image data compressed using the Modified Huffman (MH) encoding defined in ITU-T Recommendation T.4, which assigns variable-length codes to run lengths of consecutive white or black pixels along each scanline. The standard resolution for Group 3 fax is 204x98 dpi (normal mode) or 204x196 dpi (fine mode), reflecting the capabilities of thermal and laser fax machines of the era. FAX files encountered digitally are often raw Group 3 encoded bitstreams or TIFF wrappers with CCITT Group 3 compression (TIFF compression tag 3). The Group 3 encoding scheme is highly efficient for typical business documents — pages with mostly white space and black text — achieving compression ratios of 10:1 to 20:1 compared to uncompressed bitmaps. One advantage is universal fax system compatibility: Group 3 encoding is the mandatory baseline for all fax machines worldwide, meaning FAX files contain data in exactly the format transmitted over telephone lines, preserving the original fax data without transcoding losses. The format's role in business communications history provides another dimension — billions of fax transmissions using this encoding moved legal documents, medical records, and business correspondence for decades, and archived FAX files represent an important documentary record. FAX images can be viewed and converted using LibreOffice, ImageMagick, GIMP, and standard document management systems.
Developer: ITU-T
Initial release: 1980

Frequently Asked Questions

Why convert CID to FAX?

FAX format produces monochrome bitmaps compatible with fax transmission standards — useful when CJK character samples need to be faxed in documents.

How do I view FAX images?

Windows Fax Viewer, IrfanView, GIMP, and ImageMagick can open FAX-encoded images. Most fax software and machines read the format directly.

Is FAX format monochrome only?

Yes — fax images are black-and-white bitmaps optimized for telephone-line transmission of text and line art, including CJK characters.

Can fax machines print CJK glyphs?

CJK characters fax well due to their high-contrast stroke patterns. The monochrome encoding handles complex character structures clearly.

Is CID to FAX free?

Yes — no charge for conversion on Convertio. Upload your CID font and download the fax-ready output immediately.