It is a method of communication based on text messaging between two fax machines, the first one calling to other one to send a fax, the recipient receives a text on A4 paper and after that communication process ends.
Code-A is Telecode Communications Inc. billing for collecting CDRs and Softswitch management via TXT files, SNMP and DBMS. Code-A has its own framework designed to calculate every call and not to miss any.