EXHIBIT 4.10

SUMMUS [LOGO]
434 Fayetteville Street, Suite 600, Raleigh, NC  27601




                                November 18, 2005


 LAP Summus Holdings LLC
 c/o Liberty Associated Partners, L.P.
 3 Bala Plaza East, Suite 502
 Bala Cynwyd, PA 19004
 Attn.: Scott G. Bruce



          We refer to the Securities  Purchase  Agreement,  the Security
 Agreement and the  Registration  Rights  Agreement each dated as of the
 date hereof among you, us and the other parties  referenced  therein as
 well as to the 6% Senior Secured  Debenture (the  "Debenture")  and the
 Stock  Purchase  Warrants  granted by us to you on the date hereof (all
 these documents together the "Transaction Documents").

          As an inducement  to your  participation  in the  transactions
 contemplated by the Transaction  Documents,  we hereby  acknowledge and
 agree that we will  promptly (and in any event within ten days) on your
 written  request  name  any  person  you  designate  to  our  Board  of
 Directors,  and we hereby  agree  that we will use our best  efforts to
 cause  such  person (or any  substitute  person  you  designate)  to be
 elected to and  thereafter  remain on our Board of  Directors  for such
 period  of time as you own the  Debenture  or own or have the  right to
 acquire at least ten  percent  of the  shares to which you  immediately
 after  issuance of the  Debenture  have the right to acquire  under the
 warrants issued in connection  with the Debenture.  Such designee shall
 also be nominated to any  executive  (or  comparable)  committee of the
 board,  and any  other  committee  that  the  board  determines  in its
 judgement and will be promptly furnished with all information  provided
 by the Company to the other  members of the Board of  Directors or such
 committee.  In addition,  such  designee  shall have notice of, and the
 right to observe  meetings of any other  committees  of the board,  and
 shall be promptly furnished with all information provided to members of
 such  other  committees.  The  failure  to be in  compliance  with this
 undertaking  will  constitute a "default"  under any of the Transaction
 Agreements.

          We further acknowledge and agree that LAP Summus Holdings, LLC
 and its partners, affiliates and affiliates of its partners engage in a
 wide  variety  of  activities  and  have   investments  in  many  other
 companies,  some of which may be  competitive  with our  business.  LAP
 Summus Holdings,  LLC shall not be liable for any claim arising out of,
 related to or based upon,  (a) the  investment by LAP Summus  Holdings,
 LLC in any



                                  Summus, Inc.
     main office: 919.807.5600 o toll free: 877.463.3253 o fax: 919.807.5601
                                 www.summus.com
<PAGE>



entity competitive to Summus, Inc. or (b) actions taken by any partner,
officer or other  representative of LAP Summus Holdings,  LLC to assist
any such competitive company, whether or not such action was taken as a
board member of such competitive  company or otherwise,  and whether or
not such action has a detrimental effect on Summus,  Inc. The foregoing
limitation  shall not apply in the event that such claim  arises out of
or  relates to a breach by LAP Summus  Holdings,  LLC of any  agreement
with  us,   including  the  agreement  not  to  disclose   confidential
information of Summus, Inc.


                                               Very truly yours,

                                               /s/ Donald T. Locke

                                               Donald T. Locke
                                               Chief Financial Officer