What is configured in the TMA1 for stop bits and baud rate? Are you sure it is 1 and 9600?
[Link: manualslib.com]Can you post an example of the script you are attempting to use here (a simple test harness, not your full config) for a double-check? I want to see the ordering of your calls. However, I must admit that the data you are seeing does not match values where bits would be shifted in the stream.
With regard to using send and receive on the RFX9600, you might want to be aware of this.
[Link: remotecentral.com]serial.receive("abc",8,5000)
will cause the serial port to be flushed whereas
serial.receive("",8,5000)
will not flush the buffer.
serial.receive(null,8,5000)
if null is accepted as valid, will also not flush the buffer.