If you are looking to buy books for BSL TTA exams, there are only very limited titles available.Even they are out of stock.
The books that are currently available now are
1)Telecom Technical Asst (TTA) Guide -http://www.infibeam.com/Books/telecom-technical-asst-tta-guide-rph-editorial-board/9788178124513.html @ Rs.205
2) TTA (BSNL) Recruitment Exam. Pratice Papers - http://www.snapdeal.com/product/tta-bsnl-recruitment-exam-pratice/504042 @ Rs.67
If you are looking to get books only from Flipkart, here are few others books available for technical telecom assistant exam (these are currently out of stock but you can place an order & get it delivered once its restocked)
1) http://www.flipkart.com/gateway-bsnl-tta-synopsis-multiple-choice-questions-their-explanatory-notes/p/itmdhzmrtckuvmge -Gateway to BSNL TTA (Synopsis, Multiple Choice Questions and their Explanatory Notes) @ Rs.500
2) Practice workbooks - http://www.flipkart.com/bsnl-tta-telecom-technical-assistants-exam-2013-practice-workbook-general-ability-test-basic-engineering-specialization-10-mock-tests-1-past-paper/p/itmdkbhzqsjm2yrs -BSNL TTA Telecom Technical Assistants Exam 2013 Practice Workbook: (10 Mock Tests + 1 Past Paper) @ Rs.171