(BER) ASN.1 encoding rules for producing self-identifying and self-delimiting transfer syntax for data structures described in ASN.1 notations.
BER is an self-identifying and self-delimiting encoding scheme, which means that each data value can be identified, extracted and decoded individually.
Huw Rogers once described BER as "a triumph of bloated theory over clean implementation". He also criticises it as designed around bitstreams with arbitrary boundaries between data which can only be determined at a high level.
Documents: ITU-T X.690, ISO 8825-1.
See also CER, DER, PER.