Exhibit 10.11

DOMAIN NAME ASSIGNMENT

This Domain Name Assignment is delivered pursuant to the Closing under that
certain Purchase Agreement (the “Agreement”) dated as of December 18, 2003,
between Aether Systems, Inc., as the “Seller”, and TSYS Acquisition Corp., as
the “Purchaser”. Capitalized terms used in this Domain Name Assignment have the
same meanings given to them in the Agreement.

The Seller has delivered this instrument signed by the Seller to enable the
Purchaser to file it with any appropriate agency to indicate ownership of the
Intellectual Property described below and for the other purposes set forth in
this instrument. This instrument supplements and is in addition to all other
rights of the Purchaser under the Agreement and other instruments of transfer
delivered in connection with the Agreement.

The Seller has adopted and registered the Internet domain names listed on the
attached Annex A (the “Domain Names”) with Network Solutions, Inc., Register.com
or other registrars throughout the world (each a “Registrar”) on various dates.

For good and valuable consideration, receipt of which the Seller acknowledges,
and by signing and delivering this instrument, the Seller sells, assigns,
transfers, conveys, and delivers to the Purchaser all of the Seller’s right,
title and interest in and to the Domain Names and agrees as follows:

     1.     Successful Transfer. Within ten (10) business days after the Closing
Date, the Seller shall commence, or have commenced, the formal transfer of the
Domain Names to the Purchaser in accordance with the applicable domain name
transfer procedure of each Registrar (the “Transfer Procedure”). As part of the
Transfer Procedure, the Seller shall use commercially reasonable efforts to
complete, execute and deliver the applicable registrant name change agreement
utilized by each Registrar (the “Change Agreement”) in a timely manner.

          (a) The Seller agrees that, for no additional compensation, the Seller
will execute any and all documents that may be necessary or appropriate to
perfect the Purchaser’s rights in and to the Domain Names, including but not
limited to all documents that may be necessary or appropriate to effect the
formal transfer of the Domain Names to the Purchaser in accordance with the
Transfer Procedure. In connection with the Transfer Procedure, the Seller will
provide any information required or requested by the Registrar or the Purchaser,
including but not limited to, the name or names identified by the Purchaser for
billing, administrative and technical contacts.

          (b) At any time, and from time to time after the Closing, the Seller
agrees, promptly upon the Purchaser’s written request, to take any and all steps
reasonably necessary to execute, acknowledge and deliver to the Purchaser any
and all further instruments and assurances necessary to complete a Successful
Transfer. “Successful Transfer” means for this purpose that Purchaser owns and
is accurately recognized as the registrant of the Domain Names in the Network
Solution, Inc.’s WHOIS database; that the Purchaser has all rights, title and
interest in and to the Domain Names; and the Purchaser is able to use or allow
others to use the Domain Names.

     2.     Cease Use of Names. As of the Closing Date, the Seller will stop all
use of the Domain Names for any purpose, including, but not limited to, use for
an Internet site or for electronic mail. The Seller shall not adopt any new uses
of the Domain Names.

     3.     Non-Interference. Except as permitted under that certain Trademark
License Agreement executed between Seller and Purchaser on December    , 2003,
Seller agrees not to challenge or object to the Purchaser’s (a) right to
register, use, own or transfer the Domain Names anywhere in the world, or

 

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(b) right to register, use, own or transfer any trademarks, service marks,
domain names or trade names that include or consist of the Domain Names anywhere
in the world. The Seller also agrees not to take any action that would interfere
with any rights the Purchaser may have or acquire in the Domain Names and marks.

The undersigned has signed this Domain Name Assignment on January 13, 2003.

Aether Systems, Inc.:

     

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      By:   /s/ David S. Oros    

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Name:   David S. Oros    

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Title:   Chief Executive Officer    

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STATE OF MARYLAND
CITY OF BALTIMORE

On                 before me, Patricia C. Sweeting (the undersigned notary),
personally appeared David S. Oros personally known to me (or proved to me on the
basis of satisfactory evidence) to be the person(s) whose name(s) is/are
subscribed to the within instrument and acknowledged to me that he/she/they
executed the same in his/her/their authorized capacity(ies), and that by
his/her/their signature(s) on the instrument the person(s), or the entity upon
behalf of which the person(s) acted, executed the instrument.

WITNESS my hand and official seal.

[seal]

Patricia C. Sweeting

Notary Public

 

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Annex A

              DOMAIN NAME   REGISTRATION DATE   RENEWAL DATE   OWNER/DIVISION(S)

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docupro.com   9/13/02   1/5/04   Aether Systems, Inc./EMS              
futurespager.co.uk   3/17/1995   3/17/2005   Futures Pager Limited              
futurespager.com   3/31/1999   3/31/2004   Futures Pager Limited              
gotxt.co.uk   9/12/2001   9/12/2005   Sila Management Services              
gotxt.com   9/12/2001   9/12/2006   Sila Management Services              
gotxt.net   9/12/2001   9/12/2005   Sila Management Services              
IFX.nl   4/29/1998   —   Sila Communications Benelux B.V.               IFX.se  
112/7/1998   —   IFX Scandinavia               marketclip.com   9/16/02  
2/17/06   Aether Systems, Inc./EMS               marketstreamlive.com  
9/16/2003   9/16/2005   Aether Systems Ltd               mobeo.com   9/16/02  
9/1/04   Aether Systems, Inc./EMS               mobiquote.co.uk   3/8/2000  
3/8/2004   Futures Pager Limited               mobiquote.com   3/8/2000  
3/8/2004   Sila Communications (UK) Ltd               mobitrader.co.uk  
3/29/2000   3/29/2004   Futures Pager Limited               mobitrader.com  
3/29/2000   3/29/2004   Futures Pager Limited               pocketfutures.com  
6/10/1997   6/11/2004   Aether Systems, Inc./EMS              
portabledatascreen.com   3/10/2003   3/10/2005   Sila Communications (UK) Ltd  
            portabledatascreen.co.uk   3/10/2003   3/10/2005   Sila
Communications (UK) Ltd               silacom.co.uk   4/12/2000   4/12/2004  
Futures Pager Limited               silacom.com   4/11/2000   4/11/2005   Sila
Communications3               silacom.nl   8/30/2000   —   Sila Communications
Benelux B.V.               sila.es   1/29/2001   1/29/2004   Sila Communications
S.A.               wirelessdatascreen.co.uk   3/10/2003   3/10/2005   Sila
Communications (UK) Ltd               wirelessdatascreen.com   3/10/2003  
3/10/2005   Sila Communications (UK) Ltd               Silacom.biz   7/11/2001  
6/11/2003   Sila Technology Ltd4

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3 This appears to be intended to be held in the name of Sila Communications
Limited but was registered in the name “Sila Communications”

4 Searches of the WHOIS database operated by Network Solutions, LLC. on 17
December 2003 indicate that the status of this domain name is “pending”.