A substitute check or cheque, also called an image cash letter (ICL), clearing replacement document (CRD), or image replacement document (IRD), is a negotiable instrument used in electronic banking systems to represent a physical paper cheque (check). It may be wholly digital from payment initiation to clearing and settlement or it may be a digital reproduction (truncation) of an original paper check.
Software providers have developed "Virtual Check 21" standards within electronic banking systems which allows creation and submission of demand draft documents to the bank of deposit.
Standards may include:
The beginnings of substitute checks in the United States were formalized by the Check 21 Act in 2003.