This report explains the operation of the DABS uplink encoder and provides information useful in diagnosing its performance. Several techniques which may be useful in analyzing encoder operation are presented. One technique involves only the use of address-parity tables and modulo-2 addition. The address-parity tables included are based upon the encoding polynomial prescribed in "Provisional Signal Formats for the Discrete Address Beacon System," Lincoln Laboratory Project Report ATC-30 Rev. 1, dated 25 April 1974. The error detection and correction properties of polynomial encoding schemes are not the subject of this report.