Call detail recording (CDR) is a means of capturing telephone system information on calls made, including who made the call, where it went and what time of day it was made, for processing into meaningful management reports. With such information, it is easier to spot exceptions to regular calling patterns such as out-of-hours calling, international calls, significant variances from previous reporting periods and call destinations that do not reflect normal calling patterns for the enterprise. Also known as station message detail recording (SMDR).