Series 2 requires the digital converter box to record from antenna and only on 1 channel.
Series 3 (models TCD648, TCD652, and TCD658) and Premiere (models TCD746320, TCD746500, TCD748000) does record from 2 channels at once from antenna or cable or from 1 of each.
But, Premiere 4 (TCD750, TCD758) can only work on digital cable, no antenna.
Series 2 (PLS, sold)
TiVo HD 1TB (157 HD Hrs, PLS, "652")
Roamio! Oh, wait, Its Juliet!
OTA! OTA! OTA!
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!