From 1st February 2011, SBI (State Bank of India) is introducing IVR One time password for SBI Cards. This will give all SBI card holders an additional security. This will be done thru all SBI cards transaction in IVR and mobile.
This feature is suggested by RBI (Reserve bank of India) so this rule will be followed by all bank in India.
We mostly use same password for each transaction sometimes we change but form 1st February you will have generate a 6 digit number every time you do a transaction. OTP (One Time Password will be sent to your mobile number) and the OPT will be valid only for 12 hours. So for next transaction you will be needed to generate another 6 digit number.
You have to update your mobile number again for IVR service, you can do this by visiting http://www.sbicard.com/ and clicking on IVR one time password link.