The Murray code also introduced what became known as "format effectors" or "control characters" the CR (Carriage Return) and LF (Line Feed) codes. A few of Baudot's codes moved to the positions where they have stayed ever since: the NULL or BLANK and the DEL code. NULL/BLANK was used as an idle code for when no messages were being sent, but the same code was used to encode the space separation between words. Sequences of DEL codes (fully punched columns) were used at start or end of messages or between them, allowing easy separation of distinct messages. (BELL codes could be inserted in those sequences to signal to the remote operator that a new message was coming or that transmission of a message was terminated).