The SN74LS247 is a BCD-to-Seven-Segment Decoder/Drivers.
The LS247 composes the 6 and 9 with the tails. The LS247 has active-low outputs for direct drive of indicators.
The LS247 features a lamp test input and have full ripple-blanking input/output controls. An automatic leading and/or trailing-edge zero-blanking control (RBI and RBO) is incorporated and an overriding blanking input (BI) is contained which may be used to control the lamp intensity by pulsing or to inhibit the output’s lamp test may be performed at any time when the BI/RBO node is at high level. Segment identification and resultant displays are shown below. Display pattern for BCD input counts above 9 are unique symbols to authenticate input conditions.