Hi Minnie,
T1 consists of 24 channels (unlike its counterpart E1 which has 32 channels) each of 64K.
Cell planning can be learnt from a book by William LEE. Though you can get variety of vendor planning manuals, make some freinds with your local mobile operator’s network design group. That would be greatly helpful.
Number of T1s required depends on the site configration and the BSS vendor. On an average 1 T1 would be good for an average site..but again which is dependent on the calculations.
Revert incase if you require more information.
Best regards,
Garry !!