My understanding is that systems designated as "Duo" by DiSH are usable by 2 users independently from each other. There's the Duo ViP222, the DuoDVR ViP722, etc. They actually started in with Duos way back with the 322/522. Through this time they also referenced single-user only units as Solo, such as SoloDVR ViP612. The 612 is HD-DVR and has 2 tuners but does not do 2 users, thus it is a Solo. The 722 also has dual tuners
and is a Duo because 2 users.
View and Download Dish Network DuoDVR 522 instruction manual online.
manualmachine.com
Dish Network SoloDVR ViP 612 Manual Online: link, Timer Types, Timer Frequency, Timers And Recordings, Timer Priorities. On Page 49. This Timer Type Allows You To Record To The External Device, Instead Of Recording To The Receiver's Hard Drive. • Reminder—Creates An On-Screen Reminder...
www.manualslib.com
This implies that the Hopper Duo can serve 2 users. I would presume in same manner as with ViP Duos. If not then they've changed or corrupted the meaning of Duo. It doesn't mean dual tuner, it means dual user.
Get the lowdown on the differences between DISH's Hopper 3 and Duo DVR systems.
www.providercheck.net