the 46a 47a and ls47 feature active-low outputs designed for driving common-anode leds or incandescent indicators directly. the 48 ls48 and ls49 feature active-high outputs for driving lamp buffers or common-cathode leds. all of the circuits except ls49 have full ripple-blanking input/output controls and a lamp test input. the ls49 circuit incorporates a direct blanking input. segment identification and resultant displays are shown below. display patterns for bcd input counts above 9 are unique symbols to authenticate input conditions. the 46a 47a 48 ls47 and ls48 circuits incorporate automatic leading and/or trailing-edge zero-blanking control (rbi\ and rbo\). lamp test (lt\) of these types may be performed at any time when the bi\/rbo\ node is at a high level. view all in datasheet