Leo,

To be honest was never able to reliably transmit data. There were many many errors.

I have since found out a few pieces of information that I have not yet had a chance to try. Firstly, do not use the onboard osc output to run your MCU. Make sure the osc output is switched off. Apparently it creates noise in the transmission.

Also the setup is crucial, there is a lot of trial and error needed to get the settings right.

There is a lot of very valuable information here Most of the code is in C, but there is a forum, and a lot of information related to setup that you will need.

The datasheets will need to be read many many times.

I have some code that uses PBP's SEROUT commands to communicate with the RFM12, and currently it kind of works. I would suggest you try write it yourself, as you will get a much better understanding, but let me know if you really need it. It might even give me the kick I need to have another look at it.

Cheers

Dave