Download here SPM-D2 Whats's New document
Technical Manual
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SPM-D2 is a drop-in 1:1 replacement: some housing, same wiring I/O, same front plate, same configuration masks.
Additional: SPM-D2 can be configured via USB with ToolKit Software
You can identify an old SPM-D by looking on housing side, there was a RJ45 port. New SPM-D2 has a USB Port.
SPM-D replacement partnumbers can be get here:
https://easygen.org/legacy-product-replacement/