olemus
ISO/IEC 2382:
kahendkoodesitus, milles iga kümnendnumber esitatakse kahendarvuga
= binary-coded notation in which each of the decimal digits is separately represented by a binary numeral

näiteid
17₁₀ kood on 0001 0111_BCD , kuid
17₁₀ väärtus kahendarvuna on 10001₂

ülevaateid
https://en.wikipedia.org/wiki/Binary-coded_decimal
https://www.electronics-tutorials.ws/binary/binary-coded-decimal.html