6K Accessories - EVM32 "GND" and "RTN" Connections
When installing an EVM32 and its applicable SIMM cards, the documentation will refer to GND connections.
On newer EVM32 and SIMM modules, this nomenclature was changed to RTN to denote "return". This is due to some modules have isolated I/O points such as the SIM8-OUT-HCR modules which allow isolation between the different I/O points.