packet switching node in a communication system includes apparatus for receiving incoming information packets or frames which contain header portions with formatting control blocks . information in the frame &# 39 ; s header contains frame alteration commands for modifying the information in the frame . the modifications include adding new information , deleting information , and overlaying information . decoders and control devices in an alteration engine interpret the commands and apply the modifications to the frame data . common and standard data patterns are stored for insertion or overlaying to conserve data packet space .