You were right, the RTC was first designed for the Telestrat.
Here is what I found in Theoric magazine:
http://download.abandonware.org/magazin ... e%2012.jpg
http://download.abandonware.org/magazin ... e%2013.jpg
Interesting for Fabrice Broche's progarmme, but no information about the RTC itself (which chip, how to connect, etc.)
The expected article for the Atmos ("Nous verrons prochainement comment simuler la commande CLOCKSET sur ORIC-1 ou ATMOS") seems to have never been published.
