<TABLE> <S> <C>

<PAGE>

<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM XIRCOM,
INC.'S FORMS 10-Q FOR THE PERIODS ENDED DECEMBER 31, 1998, MARCH 31, 1999, AND
JUNE 30, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS. THE INTERIM STATEMENTS FOR THE PERIODS ENDED DECEMBER 31, 1998,
MARCH 31, 1999, AND JUNE 30, 1999 HAVE BEEN RESTATED TO REFLECT THE COMBINATION
OF XIRCOM, INC. AND ENTREGA TECHNOLOGIES, INC., UNDER POOLING-OF-INTERESTS
 ACCOUNTING.
</LEGEND>
<MULTIPLIER> 1,000

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          SEP-30-1999             SEP-30-1999             SEP-30-1999
<PERIOD-START>                             OCT-01-1998             OCT-01-1998             OCT-01-1998
<PERIOD-END>                               DEC-31-1998             MAR-31-1999             JUN-30-1999
<CASH>                                         124,844                 117,483                 130,182
<SECURITIES>                                         0                       0                       0
<RECEIVABLES>                                   38,190                  43,080                  54,898
<ALLOWANCES>                                     8,852                   8,512                   8,302
<INVENTORY>                                     17,666                  19,335                  15,044
<CURRENT-ASSETS>                               188,041                 189,682                 209,155
<PP&E>                                          54,458                  56,034                  60,994
<DEPRECIATION>                                  23,956                  24,164                  29,945
<TOTAL-ASSETS>                                 219,222                 226,217                 244,895
<CURRENT-LIABILITIES>                           54,454                  67,825                  74,843
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                            24                      24                      24
<OTHER-SE>                                     155,628                 149,252                 160,912
<TOTAL-LIABILITY-AND-EQUITY>                   219,222                 226,217                 244,895
<SALES>                                         98,498                 200,370                 308,809
<TOTAL-REVENUES>                                98,498                 200,370                 308,809
<CGS>                                           59,064                 117,707                 179,341
<TOTAL-COSTS>                                   59,064                 117,707                 179,341
<OTHER-EXPENSES>                                28,308                  58,343                  91,138
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                                  92                     211                     370
<INCOME-PRETAX>                                 11,410                  25,082                  39,646
<INCOME-TAX>                                     3,801                   8,012                  12,712
<INCOME-CONTINUING>                              7,609                  17,070                  26,934
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     7,609                  17,070                  26,934
<EPS-BASIC>                                        .32                     .71                    1.12
<EPS-DILUTED>                                      .30                     .67                    1.06


</TABLE>