Editing Error correction mode

{{Unreferenced|date=December 2009}}
'''Error correction mode''' ('''ECM''') is an optional [[transmission mode]] built into Class 1/2/2.0 [[fax machine]]s or [[fax modem]]s.  ECM automatically detects and corrects [[transmission error|errors]] in the fax transmission process that are sometimes caused by [[telephone line]] [[noise]]. 

The page data is divided into what is known as Octets (small [[Block (telecommunications)|blocks of data]]). Once the [[Receiver (information theory)|receiver]] has received all the Octets it examines them (using [[check-sum]]s) and then advises the transmitting fax of any Octets that are in error. The transmitter then need only resend the blocks in error rather than the whole page. This generally means an ECM coded fax will be more likely to succeed in transmitting a copy of the page(s) on a noisy line. ECM is the norm rather than the exception. Some fax machines have the capability to enable or disable this function.

{{DEFAULTSORT:Error Correction Mode}}
[[Category:Fax]]
[[Category:Error detection and correction]]

{{Telecomm-stub}}