  This document provides a brief description of the National Institute of
Standards and Technology (NIST) speaker recognition evaluation (SRE)
conversational telephone speech (CTS) Superset. The CTS Superset has been
created in an attempt to provide the research community with a large-scale
dataset along with uniform metadata that can be used to effectively train and
develop telephony (narrowband) speaker recognition systems. It contains a large
number of telephony speech segments from more than 6800 speakers with speech
durations distributed uniformly in the [10s, 60s] range. The segments have been
extracted from the source corpora used to compile prior SRE datasets
(SRE1996-2012), including the Greybeard corpus as well as the Switchboard and
Mixer series collected by the Linguistic Data Consortium (LDC). In addition to
the brief description, we also report speaker recognition results on the NIST
2020 CTS Speaker Recognition Challenge, obtained using a system trained with
the CTS Superset. The results will serve as a reference baseline for the
challenge.
