works for me.
Excellent, voltage divider it is then.


you could protect against divider failure with a 3 to 5v zenner if you are paranoid
Yes I do fit into that category (mildly at present), will look at at a backup with Zenner.


the first pic may be unnecessary too if the tx works like i think it does
I hear what your saying Richard, so I need to built the Tx cct on the bench now and test the Tx driven directly by voltage diver (no pic).

Thanks for your help, appreciated.

David