The NM-HD-2V do not support any T1 card. So you have to use the NM-HD-2VE enhanced module. This module will support upto 24 g711 voice channels with medium and 18 voice channels with high codec complexity.
The NM-HDV-1T1-24 has two PVDMs by default and will support upto 24 g711 voice channels with medium codec complexity. However you can add two more PVDMs onboard and increase the capacity to support 24 voice channels with high codec complexity. On the signaling side, this card support T1 FG-D whereas the NM-HD-2VE doesn't.
Please check these two links for more information:
http://www.cisco.com/en/US/partner/products/hw/modules/ps5365/products_data_sheet09186a0080191d41.html
http://www.cisco.com/en/US/partner/products/hw/routers/ps259/products_data_sheet09186a0080194e20.html
Thanks,
Partha