This part is a kind of semiconductor called 6SE6400-xxxxx-0AAx.
Function of this product has Pulse Encoder Evaluation Module.
Manufacturers : ETC
Image and pinout :

Some of the text within the PDF file :
s Ordering Data for Variant Independent Options The options listed here are suitable for all MICROMASTER 440 Inverters. Options Basic Operator Panel (BOP) Advanced Operator Panel (AOP) PROFIBUS module DeviceNet module Pulse encoder evaluation module RS485/PROFIBUS bus connector Connection set for PC to inverter Connection set for PC to AOP Inverter-door mounting kit for single inverter control AOP-door mounting kit for multiple inverter control (USS) Order No. 6SE6400-0BP00-0AA0 6SE6400-0AP00-0AA0 6SE6400-0AP00-0AA1 (available from mid 2002) 6SE6400-1PB00-0AA0 6SE6400-1DN00-0AA0 6SE6400-0EN00-0AA0 6GK1500-0FC00 6SE6400-1PC00-0AA0 6SE6400-0PA00-0AA0 6SE6400-0PM00-0AA0 6SE6400-0MD00-0AA0 Technical data of the communications modules PROFIBUS module 6SE6400-1PB00-0AA0 Devic [ ... ]
6SE6400-xxxxx-0AAx PDF Datasheet Download
