Thanks for the replies. Here is a link to the level: **broken link removed**
As you might know, Sears puts all its tools on sale constantly. I paid about $24 for it last Spring. The actual sensor element is a Memsi MXD2020E/FL, Both the sensor board and controller board have microcontrollers on them. The sensor I believe is an 8051 (marked F301) -- not completely sure of either. I show what the data looks like in my earlier post. The display board is a COB glob.
The 12F509 directly interrogates the sensor (i.e., no RF link). That was done for development purposes. Once I get the control module timing solved, I can probably do away with that. I suspect the sensor simply sends raw PWM and temperature information in digital. The control module seems to do all of the calculations. I have not decoded the data, except to know that the first 8 bits are a repeat of the query and the last few bits look like noise.
I briefly thought of separating the LCD display and simply making that the remote. That is still a possibility, but I would probably end up having to buy a new LCD display, as the one on the unit would probably be destroyed in removing it to get at the data lines to it.
@KISS
There are two controls, CTS and RTS (plus RO) for hardware flow control. My understanding is that CTS operates on the transmitter side and the RTS on the receiver side. xBee sends a CTS to the MCU when it is ready for more data. That is not the issue here.
In this case, it is simply my grasp of the meaning/use of the RTS control on the receive end, Or, alternatively, whether the functionality I need is available at another pin. I had read many applications for xbees, but haven't studied them deeply. They seemed to be a pretty versatile units. That is why I bought them.
Remember, I have only had my pair since the weekend and have barely scratched the surface, like learning how to set them to 14,400 baud. They really are neat, but have significant latency because of the communication protocol overhead. So far, I have not been tempted to return to the Linx I tried in the Spring.
John