IEC 61869-6:2016(E) is a product family standard and covers only additional general requirements for low-power instrument transformers (LPIT) used for a.c. applications having rated frequencies from 15 Hz to 100 Hz covering MV, HV and EHV or used for d.c. applications. This product standard is based on IEC 61869-1:2007, in addition to the relevant product specific standard. This part of IEC 61869 does not cover the specification for the digital output format of instrument transformers. This part of IEC 61869 defines the errors in case of analogue or digital output. The other characteristics of the digital interface for instrument transformers are standardised in IEC 61869-9 as an application of the standards, the IEC 61850 series, which details layered substation communication architecture. This part of IEC 61869 considers additional requirements concerning bandwidth. General Requirements; however, the reader is encouraged to use its most recent edition. This first edition of IEC 61869-6 cancels and replaces the relevant parts of IEC 60044-7, published in 1999, and of IEC 60044-8, published in 2002.This publication is to be read in conjunction with IEC 61869-1:2007