The 74LS48 feature active-high outputs for driving lamp buffers or common-cathode LEDs. They have full ripple-blanking input/output controls and a lamp test input. Display patterns for BCD input counts above 9 are unique symbols to authenticate input conditions.  Their 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. They contain an overriding blanking input (BI), which can be used to control the lamp intensity by pulsing or to inhibit the outputs. Inputs and outputs are entirely compatible for use with TTL logic outputs.

Segment identification and resultant displays is as shown below.

Features

The 74LS48 features include;

• Internal Pull-Ups Eliminate Need for External Resistors
• Lamp-Test Provision
• Leading/Trailing Zero Suppression
• Lamp Intensity Modulation Capability