A computerized system designed to automate and simplify the registration of securities salespersons went on line yesterday at the headquarters of the National Association of Securities Dealers.

The information bank, known as the Central Registration Depository, is expected to contain the credentials of thousands of securities dealers. Instead of filing for registration in every state in which they wish to operate, dealers will be able to file one form with the NASD under the new system. The dealer will need to go through only one screening to operate in all states using the system.

Thirty-two states, including Maryland and Virginia, have agreed to use the data bank, the NASD said. The District has not yet submitted an application. Massachusetts and Illinois, the first states to be connected, are expected to go on line this summer.

The NASD will operate the system under a contract from the North American Securities Administrators Association (NASAA), an organization comprising state securities commissioners. NASAA President Thomas L. Krebs said the data bank "will give the states much better information on brokers operating in their jurisdictions, relieve the state securities commissions of needless paperwork and allow them to devote more time to policing local markets."