EXHIBIT 10.5

February 2, 2001

PERSONAL AND CONFIDENTIAL                                      Via Hand Delivery

Danny L. Parker
103 Kazmann Court
Cary, North Carolina 27513

Dear Danny:

     On  behalf  of  Tekelec,  I am  pleased  to offer  you  employment  as Vice
President,   Corporate  Development  (salary  grade:  E21),  on  the  terms  and
conditions set forth in this letter. As Vice President,  Corporate  Development,
you will  report  directly  to  Tekelec's  Chief  Executive  Officer and will be
principally  responsible  for  assisting  the  Company in  connection  with such
corporate  development  projects and other duties and responsibilities as may be
delegated  to you from time to time by the Chief  Executive  Officer  and/or the
Board of Directors.  Your principal  office will be located in our  Morrisville,
North Carolina facility.  Your  responsibilities  will from time-to-time require
frequent travel.

     Your  compensation  and benefits,  effective as of your  acceptance of this
letter as evidenced by your signature below, will be as follows:

10.  Your annual base salary will continue to be $200,000  (i.e.,  $7,692.31 per
     bi-weekly period).

11.  You will be eligible to  participate  in Tekelec's 2001 Officer Bonus Plan,
     under which you will be eligible to receive,  in accordance  with the terms
     of such  Plan as  approved  by the  Company's  Board  of  Directors  (which
     approval is expected no later than in February 2001), (A) quarterly bonuses
     in 2001 equal to 40% of your quarterly  earnings for a calendar  quarter if
     the Company  achieves  certain  quarterly  financial  milestones and (B) an
     annual  bonus  equal to 10% of your 2001  annual  earnings  if you  achieve
     certain  objectives  during 2001.  The terms of your  participation  in any
     officer  bonus plans for post - 2001  periods will be subject to change and
     the approval of the Board of Directors of Tekelec.

12.  You will receive applicable benefits,  including personal time off, health,
     dental, vision,  long-term disability and life insurance,  as are generally
     provided to Tekelec's executive officers.

13.  You will  continue to have the  opportunity  to  participate  in  Tekelec's
     Employee Stock Purchase Plan and 401(k) Plan.

14.  You will be eligible for benefits under Tekelec's Officer Severance Plan (a
     copy of which has been previously  provided to you) as an Eligible  Officer
     (as defined in such Plan).  For purposes of determining your benefits under
     the Officer  Severance  Plan,  your  Employment  Period (as defined in such
     Plan) will  include the period of time  commencing  in October  2000 during
<PAGE>

                                                                    EXHIBIT 10.5

     which  you  served  as Vice  President,  as well as the  period of time you
     previously   served  as  Vice  President  and  General   Manager,   Network
     Diagnostics Division.

     This letter agreement contains our entire  understanding and agreement with
respect  to your  employment  with  Tekelec  commencing  on your  Start Date and
supercedes  and  replaces any and all prior or  contemporaneous  oral or written
communications  with respect  thereto.  Without  limiting the  generality of the
foregoing,  you  acknowledge  and agree that upon your acceptance of this letter
agreement,  that certain  letter  addressed to you from  Tekelec,  dated October
2000, pursuant to which you served as Vice President of Tekelec, shall terminate
and shall not apply to your  employment  as  contemplated  herein.  There are no
promises  or  understandings,  express  or  implied,  concerning  your  proposed
employment  with Tekelec  except as set forth  herein.  The  provisions  of this
letter may be amended only by a writing signed by you and by the Chief Executive
Officer  or the  Chairman  of the Board of  Directors  of  Tekelec  on behalf of
Tekelec.  If you have any  questions  about the  meaning  of any of the terms or
provisions  included  herein,  please let me know at your earliest  convenience.
This letter agreement shall be construed under the laws of California.

     Danny,  we believe that your continued  employment with Tekelec can provide
you with  opportunities  for professional  growth and financial  return. As with
every Tekelec  employee,  you reserve the right to terminate your  employment at
any time for any reason,  and we similarly  reserve the right to terminate  your
employment at any time, with or without cause. We hope and expect, however, that
this will be a long and mutually beneficial relationship.

     If this letter agreement is acceptable to you, then please acknowledge your
acceptance  by signing and dating the  enclosed  copy of this  letter  agreement
where  indicated  below and then returning such signed copy to me for receipt no
later than February 9, 2001.

                                        Sincerely,

                                        Michael L. Margolis
                                        Chief Executive Officer and President

Acknowledged and Accepted:

                                        Date:  February __, 2001
--------------------------------
Danny L. Parker