<ARTICLE> 5 <MULTIPLIER> 1,000 <CURRENCY> US DOLLARS <PERIOD-TYPE> 9-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> SEP-30-1998 <EXCHANGE-RATE> 1 <CASH> 40,540 <SECURITIES> 113,164 <RECEIVABLES> 30,635 <ALLOWANCES> 715 <INVENTORY> 8,214 <CURRENT-ASSETS> 203,309 <PP&E> 25,705 <DEPRECIATION> 0 <TOTAL-ASSETS> 255,990 <CURRENT-LIABILITIES> 31,343 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 414 <OTHER-SE> 221,669 <TOTAL-LIABILITY-AND-EQUITY> 255,990 <SALES> 124,419 <TOTAL-REVENUES> 124,419 <CGS> 28,874 <TOTAL-COSTS> 85,475 <OTHER-EXPENSES> 4,472<F1> <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 0 <INCOME-PRETAX> 27,981 <INCOME-TAX> 11,690 <INCOME-CONTINUING> 16,826 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 16,826 <EPS-PRIMARY> 0.41 <EPS-DILUTED> 0.40 <FN> <F1>OTHER EXPENSES REFERS TO EXPENSES OF $2,600 INCURRED IN CONJUNCTION WITH THE ACQUISITION AND INTEGRATION OF INTRUSION DETECTION INC. AND OTHER EXPENSES OF $1,872 INCURRED IN CONNECTION WITH A THREATENED LITIGATION SETTLEMENT. </FN>