Debian 8: (jessie): http://repos.rcn-ee.com/debian/
deb [arch=armhf] http://repos.rcn-ee.com/debian/ jessie main
#deb-src [arch=armhf] http://repos.rcn-ee.com/debian/ jessie main
Debian 9: (stretch): http://repos.rcn-ee.com/debian/
deb [arch=armhf] http://repos.rcn-ee.com/debian/ stretch main
#deb-src [arch=armhf] http://repos.rcn-ee.com/debian/ stretch main
Debian 10: (buster): http://repos.rcn-ee.com/debian/
deb [arch=armhf] http://repos.rcn-ee.com/debian/ buster main
#deb-src [arch=armhf] http://repos.rcn-ee.com/debian/ buster main
Ubuntu 16.04 lts: (xenial): http://repos.rcn-ee.com/ubuntu/
deb [arch=armhf] http://repos.rcn-ee.com/ubuntu/ xenial main
#deb-src [arch=armhf] http://repos.rcn-ee.com/ubuntu/ xenial main
Ubuntu 17.10: (artful): http://repos.rcn-ee.com/ubuntu/
deb [arch=armhf] http://repos.rcn-ee.com/ubuntu/ artful main
#deb-src [arch=armhf] http://repos.rcn-ee.com/ubuntu/ artful main
Ubuntu 18.04 lts: (bionic): http://repos.rcn-ee.com/ubuntu/
deb [arch=armhf] http://repos.rcn-ee.com/ubuntu/ bionic main
#deb-src [arch=armhf] http://repos.rcn-ee.com/ubuntu/ bionic main
keyring:
sudo apt-get install rcn-ee-archive-keyring