Only certain 802.11b adapters work with 6.2; 802.11g adapters will not work at all. Look here
for a list.
There's no real need for the TiVo to "phone home" with a DirecTv one; all of the guide data come from the satellite. If you want to do things such as HMO and MRV, then there is a use for a network connection, but I don't think you' ll be very happy with the speed of 802.11b with MRV. I posted a workaround for that here