PLT to FAX Converter

Convert HPGL plotter drawings to FAX image format

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Fax-Ready Drawings

Convert PLT plotter files to FAX format — ready for transmission through fax machines and digital fax services.

Effortless Workflow

Upload your PLT file, select FAX, and download. No fax software or format knowledge required on your part.

Server-Side Processing

Convertio's cloud handles the conversion — your device stays free from processing load and software installations.

How to convert PLT 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

PLT is a vector file format associated with HP-GL (Hewlett-Packard Graphics Language), a plotter control language introduced by Hewlett-Packard in 1977 with the HP-9872 pen plotter. PLT files contain a sequence of two-letter ASCII commands that instruct a pen plotter to move, draw lines, select pens, and render text — commands like PU (pen up), PD (pen down), PA (plot absolute), and SP (select pen) form a straightforward instruction set that directly controls physical drawing motion. The language operates on a coordinate grid measured in plotter units (typically 0.025 mm per unit), and the resulting files read almost like machine code for a drawing device. HP-GL became the dominant standard for computer-aided design output, adopted by virtually every CAD application and supported by plotters from all manufacturers throughout the 1980s and 1990s. One advantage is universal CAD compatibility — PLT files generated by AutoCAD, SolidWorks, or any engineering software can be sent directly to plotters and cutting machines without driver translation. The text-based, human-readable command structure is another strength: engineers can inspect, edit, and hand-write PLT files to troubleshoot output or generate simple drawings programmatically. HP-GL/2, an enhanced version introduced with the HP LaserJet III in 1990, added polygon fills, Bezier curves, and raster support. PLT remains actively used in engineering, architecture, and manufacturing for large-format output.
Developer: Hewlett-Packard
Initial release: 1977
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 PLT to FAX?

FAX format is optimized for fax transmission — converting PLT lets you send plotter drawings through fax machines and digital fax services.

What opens FAX image files?

Windows Fax Viewer, IrfanView, XnView, and most fax software handle FAX image format natively.

Is FAX a monochrome format?

Typically yes — fax images use black-and-white encoding, which suits plotter line drawings that consist of clean paths on white.

Does the conversion maintain line sharpness?

Yes — plotter lines translate well into the high-contrast fax format, producing clear and readable output.

Is PLT to FAX free?

Yes — Convertio offers free PLT to FAX conversion. No software downloads, no fees, no registration.

Does this work on Mac and Linux?

Absolutely. The converter is browser-based and runs on any operating system with internet access.