Receivers who claim conformance to the basic encoding rules shall support all alternatives".

As stated in the X.690 standard, "Alternative encodings are permitted by the basic encoding rules as a sender's option.

All information is transmitted using Basic Encoding Rules (BER).

Basic Encoding Rules defined as part of the ASN.1 as a transmission encoding standard.

Basic Encoding Rules (BER)

The Basic Encoding Rules were the original rules laid out by the ASN.1 standard for encoding abstract information into a concrete data stream.

DER is a subset of Basic Encoding Rules (BER) providing for exactly one way to encode an ASN.1 value.

The key difference between the BER format and the CER or DER formats is the flexibility provided by the Basic Encoding Rules.

The ASN.1 objects are converted into binary data streams using Medical Device Encoding Rules (MDER) which is a subset of Basic Encoding Rules (BER).

Whereas BER gives choices as to how data values may be encoded, CER (together with DER) selects just one encoding from those allowed by the basic encoding rules, eliminating rest of the options.

The original presentation structure used the basic encoding rules of Abstract Syntax Notation One (ASN.1), with capabilities such as converting an EBCDIC-coded text file to an ASCII-coded file, or serialization of objects and other data structures from and to XML.