The SDO Gateway Add-on implements a SDO gateway function,
which makes possible the SDO transfer between two or more CANopen
networks. To use this feature, the gateway device must feature at least
two CANopen instances. A so-called CANopen SDO server receives the SDO
messages of the client residing on the one side, and handles the
transfer to the targeted SDO server on the subordinated CANopen network.
The SDO response messages are handled vice versa. This implementation
of the SDO gateway does not support dynamic SDO channels.