Hi,
as per your explanation you have 1941 router. this router can have only 3 EHWIC cards. you cannot have 4 x 1T cards, but you can have 3 x 1T card if you are OK with 3 ports, or 1 x 2T card + 2 x 1T card if you needs 4 ports.
regards,
Please rate this and mark as solution/answer, if this resolved your issue
Good luck
KB