Hi nihangshah, IF you alrady have bsnl Landline connection you need not pay andy deposit for bsnl broadband connection. Otherwise You have to pay normal bsnl landline deposit which is based upon your requirement like STD,ISD.For upgrading From Home 250 to Home 500 plan no additional Deposit is needed.You can use the toll free number service offered by Bsnl and have your doubts clarified officially.