If you go into your src\bsp\platforms directory (in the tree in which NET+OS was installed), you see that each known platform has its own directory, for example, connectcore9p9215_a, ns9210_a....etc. Each of these platforms-specific directories has a file entitled rtc.c. In each file entitled rtc.c is the declaration of a table named naRtcDeviceTable. For platforms that support an RTC, this table is populated/initialized (with objects other than 0). If the platform does not support an RTC, then the table is populated/initialized with 0s (zeroes). The number of platforms that support an RTC is quite limited and is limited to the 9215-based products and 9360-based products. All other platforms have this table uninitialized, signifying that the RTC is not supported.