Hi,
As you are saying embedded architecture, I will assume that you will be doing service development as well as registration in the same system. and it would be your TM system itself. also your TM will be integrated with ECC for data flow.
I will clarify more with CRM system scenario. CRM is integrated with ECC and data flow happens with CRM middleware which insures that data is in sync between both the system. Now if I want to develop app based on CRM system using CRM data then I will have GW component installed on CRM and develop Odata service there.
I hope this will answer your question.
Regards,
Chandra