(Automatic Message Accounting) The recording and reporting of telephone calls within a telephone system. It includes the calling and called parties and start and stop times of the call. When performed in a tandem switch, it is known as "Central Automatic Message Accounting" (CAMA). When done in an end office switch, where most billing is handled today, it is known as "Local Automatic Message Accounting" (LAMA). Also known as "Call Detail Reporting" (CDR).