ASN.1 stands for Abstract Syntax Notation One.
(ASN.1) is a standard interface description language for defining data structures that can be serialized and deserialized in a cross-platform way. It is broadly used in telecommunications and computer networking, and especially in cryptography.
ASN.1 allows protocol developers to define data structures in a human-readable and machine-readable way, independent of a particular computer or programming language.
ASN.1 also provides several standardized encoding rules, such as BER, PER, XER, etc., that describe how the data structures should be encoded for transmission and decoded for interpretation.
ASN.1 was originally defined in 1984 as part of CCITT X.409:1984, and later moved to its own standard, X.208, in 1988. The latest revision of the ASN.1 standard is the X.680 series, published in 2021.
One of the applications of Asn.1 is to encode Call Detail Records (CDRs), which are the telecom switch records produced by a telephone exchange that passed through it. CDRs contain information about system usage concerning the call, such as the identities of sources and destinations, the call duration, and other pieces of information used for marketing, billing, monitoring, or fraud detection.
There are different formats and encoding rules for CDRs, depending on the network switch and the standard used. Some of the common standards are GSM-Association TAP3 and 3GPP TS 32.3298. To process CDR files, operators, system integrators, or software suppliers need tools that can convert Asn.1 encoded CDR files into XML or CSV text format that can be easily read and analyzed. There are several tools available for this purpose, such as MARBEN CDR Converter and IRI CDR File Conversion. These tools allow users to configure the output format and the conversion options for different values. They also support block size and padding byte features that may be present in some CDR files.