Hi salyersa,
RSSI (received signal strength indication) is used to measure the strength of the signal being received by a wireless module. In your case, only the C7 module has this built in capability to measure the strength of the signals it receives. The advanced feature of RSSI reporting means that the C7 module reports the received signal strength serially to its host MCU, not wirelessly to the ANTUSB2 Stick.
From your description it seems that you are under the impression that RSSI is transmitted data indicating the strength of the signal being transmitted. This is a common misconception, RSSI is actually a measurement performed by the receiver unit of the power of the signal it receives on its antenna.
Your testing summary states that only the C7 Module is capable of measuring (receiving) RSSI, this is correct. However, RSSI is not transmitted by either module, it is a measurement the C7 performs of the signal it recieves from the USB2 Stick.
Hope this explanation cleared it up.
- usamak