FAX to OTB Converter

FAX to OTB conversion online — fast and free

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Secure Processing

Source FAX files are deleted instantly after conversion. OTB output files are auto-removed within 24 hours.

Instant Results

FAX files are typically small. Cloud processing delivers your OTB output in seconds — no waiting.

Document Recovery

Extract visual content from FAX files and save as OTB — ideal for archiving important fax correspondence.

How to convert FAX to OTB

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

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

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

About formats

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

OTB (Over-the-Air Bitmap) is a monochrome image format developed by Nokia as part of their Smart Messaging specification in 1997, designed for transmitting small graphics — operator logos, group graphics, and picture messages — to Nokia mobile phones via SMS. OTB files contain 1-bit (black and white) images at small fixed resolutions, typically 72x14 pixels for operator logos and 72x28 pixels for group graphics, encoded in a compact binary format suitable for embedding within the payload of SMS text messages. The format uses a simple structure: a header byte indicating whether the image is an operator logo or group graphic, width and height values, and the raw bitmap data where each bit represents one pixel packed eight per byte. The extremely tight format — designed to fit within a single SMS message (140 bytes maximum payload, shared with addressing overhead) — reflects the severe constraints of mobile communication in the late 1990s. Nokia's Smart Messaging system was one of the first commercial implementations of rich content delivery to mobile phones, and OTB images represented the entire visual content capability of Nokia handsets before MMS and mobile data browsing arrived. One advantage is the format's historical role as a pioneer of mobile visual messaging: OTB images were among the first graphics that ordinary consumers could send to each other's phones, predating MMS, camera phones, and smartphones by nearly a decade. The format's minimal footprint is another characteristic — entire images fit in a few dozen bytes, reflecting an era of extreme bandwidth constraints. OTB files are supported by ImageMagick, various Nokia phone management tools, and specialty mobile format utilities.

Developer: Nokia

Initial release: 1997

Frequently Asked Questions

Why convert FAX to OTB?

Digitizing fax files to OTB format enables easy viewing, sharing, and embedding across modern platforms.

How can I view OTB files?

View OTB files with mobile development tools or OTA bitmap editors — all handle this format natively.

Will text remain readable after conversion?

All visual content from your FAX file is faithfully reproduced in OTB — no degradation occurs during conversion.

Is this conversion free to use?

Free for standard conversions. Upgrade to a premium plan for higher volume and priority processing capabilities.

Is batch FAX to OTB conversion available?

Yes — add several FAX files in one session. Each converts to OTB independently and downloads separately.

Can I use this converter on a Mac?

Yes — the converter runs in any browser on macOS, Windows, Linux, Android, and iOS. Fully cross-platform.

Related Conversions

FAX to PDF

FAX to JPG

FAX to TIFF

FAX to JPEG

FAX to PNG

FAX to BMP

FAX to JP2

FAX to JIF

FAX to DXF

FAX to DOT

FAX to XPM

FAX to WBMP

FAX to GIF

FAX to TGA

FAX to SVG

FAX to PCX

FAX to ICO

FAX to CUR

FAX to PBM

FAX to PGM

FAX to PPM

FAX to WEBP

FAX to EXR

FAX to FTS

FAX to G3

FAX to HDR

FAX to HRZ

FAX to IPL

FAX to MAP

FAX to MNG

FAX to MTV

FAX to OTB

FAX to PAL

FAX to PALM

FAX to PAM

FAX to PCD

FAX to PCT

FAX to PDB

FAX to PFM

FAX to PICON

FAX to PICT

FAX to PNM

FAX to PSD

FAX to RAS

FAX to RGB

FAX to RGBA

FAX to RGBO

FAX to SGI

FAX to SUN

FAX to UYVY

FAX to VIFF

FAX to XBM

FAX to XV

FAX to XWD

FAX to YUV

FAX to JBG

FAX to JBIG

FAX to HEIC

FAX to HEIF

FAX to G4

Specific converters

PDF to OTB

TTF to OTB

ODT to OTB

JPG to OTB

PNG to OTB

OTF to OTB

HTML to OTB

DOCX to OTB

RTF to OTB

JPEG to OTB

AI to OTB

XLS to OTB

BMP to OTB

BIN to OTB

SVG to OTB

PPSX to OTB

CDR to OTB

DOC to OTB

FIG to OTB

GIF to OTB

ICO to OTB

ABW to OTB

DBK to OTB

KWD to OTB

SXW to OTB

AW to OTB

3FR to OTB

ARW to OTB

AVIF to OTB

CR2 to OTB