Exhibit 99.1

         InterDigital Completes Two Million Share Repurchase;
       Five Million Shares Repurchased within a Two Year Period

    KING OF PRUSSIA, Pa.--(BUSINESS WIRE)--April 21,
2005--InterDigital Communications Corporation (Nasdaq:IDCC), a leading
architect, designer and provider of wireless technology and product
platforms, today announced that it has completed the repurchase of two
million shares of Common Stock. In October 2004, InterDigital's Board
of Directors authorized the repurchase of one million shares and, in
March 2005, expanded the authorization to a total of two million
shares.
    Since the beginning of 2003, InterDigital has repurchased 5
million shares, investing approximately $86 million. "Our pattern of
share repurchases in recent years reflects our strong commitment to
invest in the value of the Company for the benefit of our shareholders
and our confidence in the value we are creating for the future," said
Harry G. Campagna, Chairman of the Board of Directors.

    About InterDigital

    InterDigital architects, designs and provides advanced wireless
technologies and products that drive voice and data communications.
The Company offer technology and product solutions for mainstream
wireless applications that deliver time-to-market, performance, and
cost benefits, as well as product differentiation advantages, to its
commercial and government/military customers. InterDigital has a
strong portfolio of patented technologies covering 2G, 2.5G, 3G and
802 standards, which it licenses worldwide. For more information,
please visit InterDigital's web site: www.interdigital.com.
InterDigital is a registered trademark of InterDigital Communications
Corporation.

    CONTACT: InterDigital Communications Corporation
             Media:
             Dawn Goldstein, 610-878-7800
             dawn.goldstein@interdigital.com
              or
             Investor:
             Janet Point, 610-878-7800
             janet.point@interdigital.com