Exhibit 10.4

                                  GUARANTY
                                  --------

      For value  received, the undersigned  ("Guarantor") hereby  enters into
 this Guaranty  ("Guaranty")  and unconditionally  endorses,  guarantees  and
 promises to  pay to  Excellon Automation  Co. ("Excellon")  the  amounts set
 forth in tat certain  Excellon Lease Agreement  (the "Agreement")  dated May
 15,  1998  by  and  between  Excellon  and  Performance  Interconnect,  Inc.
 ("Obligor") and  all  extensions  and renewals  of  the  Agreement  and  all
 expenses, including reasonable attorneys'  fees, incurred in collecting  the
 Agreement or enforcing this Guaranty, or both.

      The  obligation  of  the Guarantor  hereunder  is  independent  of  the
 obligation of the  Obligor under  the Agreement,  and a  separate action  or
 actions may be brought or prosecuted  against the Guarantor, whether  action
 is brought against the Obligor under the Agreement or any other guarantor be
 joined in any such action or actions.

      The  Guarantor hereby  waives  any right  to  require Excellon  to  (a)
 proceed against the  Obligor under the  Agreement; or (b)  pursue any  other
 remedy in said  Excellon's power whatsoever.  Until all payment  obligations
 set forth in Section 2 of the Agreement have been performed and satisfied in
 full, Guarantor shall not waive any right of subrogation, and hereby  waives
 any right to enforce any remedy which Excellon now has or may hereafter have
 against the Obligor under the Agreement,  and waives any benefit of and  any
 right to participate  in any  security now  or hereafter  held by  Excellon.
 The Guarantor  hereby  waives  all presentments,  demands  for  performance,
 notices of  nonperformance, protests,  notices of  protest, and  notices  of
 dishonor.

      No failure or delay by  Excellon to insist upon the strict  performance
 of any  term,  condition, covenant  or  agreement  of this  Guaranty  or  to
 exercise any right, power  or remedy hereunder or  consequent upon a  breach
 hereof shall  constitute a  waiver of  any such  term, condition,  covenant,
 agreement, right, power or remedy of  any such breach, or preclude  Excellon
 from exercising any such right, power or remedy at any later time or times.

      In case any  one or more of the  provisions contained in this  Guaranty
 should be invalid, illegal  or unenforceable in  any respect, the  validity,
 legality and  enforceability of  the remaining  provisions contained  herein
 shall not in any way be affected or impaired thereby.
<PAGE>
      This Guaranty (a) constitutes the entire Agreement, and supersedes  all
 prior agreements and  understandings, both written  and oral, among  Obligor
 and Guarantor with respect to the subject matter hereof, (b) may be executed
 in several counterparts, each of which shall be deemed an original, but  all
 of which together  shall constitute  one and  the same  instrument, and  (c)
 shall be binding  upon Guarantor and  its successors and  assigns and  shall
 inure to  the benefit  of, and  shall be  enforceable by,  Excellon and  its
 successors and assigns.

      Unless   otherwise   specifically   provided   herein,   all   notices,
 instructions,  requests  and  other  communications  required  or  permitted
 hereunder shall  be in  writing and  become effective  when received  or  if
 mailed when deposited in the United States mail, postage prepaid, registered
 or certified mail, return  receipt requested.  Notices  shall be directed to
 Excellon at its address set forth in the Agreement, and to Guarantor at  its
 address set forth below, or at such  other addresses as such party may  from
 time to time furnish to the other by notice similarly given.

      This  Guaranty shall  be binding  upon  the Guarantor  and his  or  her
 successors and shall inure to the benefit of the Excellon.

      This Guaranty shall be  governed by, and construed in accordance  with,
 the laws of the State of California.

      TN WITNESS WHEREOF, the  undersigned has executed this Guaranty on  the
 date of the Agreement.


 /s/
 ---------------
 D. Ronald Allen

 Address:

 10911 Petal St., Suite 105
 Dallas, TX 75238

                                ACCEPTED BY EXCELLON AUTOMATION CO.

                                /s/
                                ---------------------------
                                         5/15/98