Error correction mode (ECM) is a feature in a fax that corrects errors in the fax transmission from bad phone connections.
The most common error is in a fax transmission is telephone line noise, which can distort the image of a fax.
With a noisy phone line, ECM can result in a higher success rate for fax transmissions.
ECM is sometimes turned off for attempting to fax over a digital phone line (such as a VoIP phone line).
How it works
ECM works in a way that is similar to an internet transmission.
With ECM enabled, the fax transmission is broken into small chunks of data. As each piece of data is sent, a confirmation of whether it was received or not is returned. Any parts of the transmission that are not fully received are sent again.
Sources and more resources
- Wikipedia – Error Correction Mode – a quick Wikipedia article with an overview on ECM fax transmissions.
- Houston Chronicle Small Business – What is Fax ECM? – an overview of ECM in fax transmissions. Written for a non-technical audience.
- T38fax Blog – T.38’s dirty little secret (and why it matters) – A discussion on whether ECM should be turned on or off. ECM is often the first option to turn off with a difficult fax line, however sometimes it may be better to leave it on.
- HP Support – Enabling and Disabling Error Correction Mode (ECM) – HP’s troubleshooting document on whether ECM should be turned on or off.
- Cisco – Fax Error Correction Mode (ECM) Product TechNote – a technical explanation of ECM in fax and how it works.
- VoIP Mechanic – How to fax over VoIP – instructions on “best practices” on sending a fax over a VoIP phone connection. Includes instructions on changing the transmission speed and enabling/disabling ECM on common fax brands.
- Konica Minolta – Sending a fax after cancelling ECM – How to cancel ECM on a Konica Minolta Multifunction printer/fax.
- Lexmark – How to disable error correction mode (ECM) for voice over internet protocol (VoIP) fax troubleshooting – Lexmark’s instructions on how to disable ECM when using a VoIP phone line.
- Brother – I am using Voice Over Internet Protocol (VoIP) and cannot send and/or receive faxes – Brother’s instructions on turning ECM on and off, and when to do so.