Dear student

A diploma holder can join B.Tech course (regular or distance) by D2D process after completing Diploma in Engineering. B.Tech program allows Diploma students to take entry directly into second year of engineering course. 

For taking admission in B.Tech, you must have done at least 3 years diploma after 10th in any branch of engineering. 

Some colleges take admission through lateral entry exams like Joint Entrance Examination of Lateral Entry (JELET), Diploma to Degree Entrance Competitive exam, etc. so you need to appear and crack these exams. Some colleges conducted their own entrance exam for getting entry. 

Admission procedure varies from college to college. So you will have to contact colleges individually.

Hope this helps

All the best !!!