RELIANCE ELECTRIC 57C442B Data Highway Plus Interface ModuleReliance Electric 57C442B Data Highway Plus Interface Module The 57C442B is a Data Highway Plus Interface Module manufactured by Reliance Electric. Here are the technical specifications for this module: Frequency: 8 MHz Memory Port: 32K dual memory port Input Rating: 5VDC at 650 mA Additional Feature: Includes a separate memory area for transmitting statistical data, which is accessible by other devices on the network. Faceplate Features: 7 segment