Altigen Call Detail Reporting Manual page 36

CDR Overview
SMDR Cautions.
SMDR is a Mitel-defined data schema for delivering
basic call information out the RS232 serial port to external recording and
reporting applications. While AltiGen has provided an SMDR interface,
it has had many problems in terms of accuracy and consistency of
information delivery. SMDR is not CDR. CDR is historical, and is a
database containing call records. SMDR is a real time delivery of a subset
of this information. We recommend that you use the new CDR, not the
SMDR, for reporting and billing applications. No improvements or
corrections have been made to SMDR.
CDR Manual 27