If you want multi-room functionality, Cox forces you to rent their DVR at $20 a month per DVR.
Normally you could use a Series 3 Tivo or an HTPC with mythtv, but Cox doesn't allow this by flagging all channels with CCI 0x02.
While you can use a series 4 tivo, they cost a lot, and its a lame solution when your existing DVR would otherwise work fine if cox left the cci flag alone, like all other cable tv companies.