Document:

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                                                                   Exhibit 10.24

                                 PROMISSORY NOTE

$200,000                                                           JULY 24, 2001

     FOR VALUE RECEIVED, CAPSULE COMMUNICATIONS, INC. with principal offices
located at 2 Greenwood Square, 3331 Street Road, Suite 275, Bensalem,
Pennsylvania 19020 hereafter referred to as the "Borrower") promises to pay to
the order of Covista, Inc. (the "Lender") at its principal office, 150 Clove
Road, Little Falls, New Jersey 07424, the sum of Two Hundred Thousand and 00/100
($200,000) Dollars (the "Principal") with interest thereon as more fully set
forth below.

     This Note shall bear interest from the date hereof and during the term
hereof at a rate of eight and three-quarter (8 3/4) percent per annum. Interest
and Principal shall be payable in full one year from the date above written (the
"Due Date").

     Occurrence of any one of the following events shall be deemed to be a
default under the terms of this Note:

     1.   Failure to pay accrued Interest or the Principal of this Note; or

     2.   Borrower shall make an assignment for the benefit of creditors or
          attempt to effect a composition or arrangement with creditors or be
          adjudged bankrupt or insolvent or any receiver, trustee, liquidator,
          conservator or like officer be appointed to take custody, possession
          or control of any property of Borrower; or Borrower shall file any
          petition, answer of other pleading in any proceeding under any
          Bankruptcy Act as now or hereafter in effect for the purpose of
          affording relief to debtors from their obligations. However, with
          respect to any event of default, as set forth in this subsection 2, no
          default shall be deemed to have occurred unless Borrower fails to cure
          such default within thirty (30) days after the occurrence thereof; or

     3.   Upon failure by Borrower to make payment on this Note at its stated
          due date, or if a default (as defined above) shall have occurred, the
          Lender may, in addition to such other and further rights and remedies
          provided by law, collect interest from the date of such maturity on
          the principal balance owing hereon at the rate of interest of five
          (5%) percent per annum in excess of that specified in this Note, but
          not in excess of the highest legal rate permitted in the State of New
          Jersey.

     This Note shall also become immediately due and payable in full on not less
than five (5) days prior written notice to Borrower if a certain proposed merger
between Borrower and Lender's subsidiary is not consummated on or prior to
December 31, 2001, or any merger agreement between said parties is terminated
prior to said date, whichever is sooner.

     If this Note is referred to an attorney for collection, regardless of
whether such attorney is an employee of the Lender, Borrower agrees that Lender
shall be entitled to collect reasonable attorney's fees and expenses for the
cost of such collection.

     This Note may be prepaid in whole or in part without penalty or premium;
however, any prepayment of less than the full principal balance hereof shall be
in the inverse order of maturity.

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     This Note shall be payable when due without defense, other than full and
legal payment, offset, deduction or claim of any kind whatsoever.

     The obligations evidenced by this Note are binding upon the Borrower, its
successors and/or assigns.

     Presentment for payment, notice of dishonor, and notice of protest are
hereby waived by the makers, and any guarantor or and endorser hereof.

     IN WITNESS WHEREOF, the undersigned has caused this Note to be executed as
of the date and year first above written.

ATTEST                                 CAPSULE COMMUNICATIONS, INC.

/s/ RANDOLPH A. FRY                    /s/ DAVID B. HURWITZ
---------------------------            -------------------------------------
                                       By: David Hurwitz
                                       Title: President & CEO

                                       2<PAGE>

                                                                   Exhibit 10.25

                                 PROMISSORY NOTE

$300,000                                                          AUGUST 9, 2001

     FOR VALUE RECEIVED, CAPSULE COMMUNICATIONS, INC. with principal offices
located at 2 Greenwood Square, 3331 Street Road, Suite 275, Bensalem,
Pennsylvania 19020 hereafter referred to as the "Borrower") promises to pay to
the order of Covista, Inc. (the "Lender") at its principal office, 150 Clove
Road, Little Falls, New Jersey 07424, the sum of Three Hundred Thousand and
00/100 ($300,000) Dollars (the "Principal") with interest thereon as more fully
set forth below.

     This Note shall bear interest from the date hereof and during the term
hereof at a rate of eight and three-quarter (8 3/4) percent per annum. Interest
and Principal shall be payable in full one year from the date above written (the
"Due Date").

     Occurrence of any one of the following events shall be deemed to be a
default under the terms of this Note:

     1.   Failure to pay accrued Interest or the Principal of this Note; or

     2.   Borrower shall make an assignment for the benefit of creditors or
          attempt to effect a composition or arrangement with creditors or be
          adjudged bankrupt or insolvent or any receiver, trustee, liquidator,
          conservator or like officer be appointed to take custody, possession
          or control of any property of Borrower; or Borrower shall file any
          petition, answer of other pleading in any proceeding under any
          Bankruptcy Act as now or hereafter in effect for the purpose of
          affording relief to debtors from their obligations. However, with
          respect to any event of default, as set forth in this subsection 2, no
          default shall be deemed to have occurred unless Borrower fails to cure
          such default within thirty (30) days after the occurrence thereof; or

     3.   Upon failure by Borrower to make payment on this Note at its stated
          due date, or if a default (as defined above) shall have occurred, the
          Lender may, in addition to such other and further rights and remedies
          provided by law, collect interest from the date of such maturity on
          the principal balance owing hereon at the rate of interest of five
          (5%) percent per annum in excess of that specified in this Note, but
          not in excess of the highest legal rate permitted in the State of New
          Jersey.

     This Note shall also become immediately due and payable in full on not less
than five (5) days prior written notice to Borrower if a certain proposed merger
between Borrower and Lender's subsidiary is not consummated on or prior to
December 31, 2001, or any merger agreement between said parties is terminated
prior to said date, whichever is sooner.

     If this Note is referred to an attorney for collection, regardless of
whether such attorney is an employee of the Lender, Borrower agrees that Lender
shall be entitled to collect reasonable attorney's fees and expenses for the
cost of such collection.

     This Note may be prepaid in whole or in part without penalty or premium;
however, any prepayment of less than the full principal balance hereof shall be
in the inverse order of maturity.

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     This Note shall be payable when due without defense, other than full and
legal payment, offset, deduction or claim of any kind whatsoever.

     The obligations evidenced by this Note are binding upon the Borrower, its
successors and/or assigns.

     Presentment for payment, notice of dishonor, and notice of protest are
hereby waived by the makers, and any guarantor or and endorser hereof.

     IN WITNESS WHEREOF, the undersigned has caused this Note to be executed as
of the date and year first above written.

      ATTEST:                            CAPSULE COMMUNICATIONS, INC.

      /s/ Randolph A. Fry                /s/ David B. Hurwitz
      ---------------------------        -------------------------------------
                                         By: David Hurwitz
                                         Title: President & CEO

                                       2<PAGE>

                                                                   Exhibit 10.26

                               INVESTOR AGREEMENT

     The undersigned, Gold & Appel Transfer, S.A. ("G&A"), hereby agrees to loan
to Capsule Communications, Inc. ("Capsule"), the sum of up to $900,000 (the
"Maximum Amount"), G&A will invest funds on the following schedule: $300,000 on
March 13, 2001 and $300,000 on May 1, 2001 and $300,000 on June 15, 2001 or
later if requested by the president of Capsule. The foregoing agreement of G&A
shall be on, and subject to, the following conditions:

     1. References below to the "Company" shall deem Capsule as the borrower of
sums from G&A.

     2. The loan shall be due and payable on or before June 15, 2002.

     3. At the option of G&A the loan can be converted at any time during the
loan period to shares of Capsule at the average trading price of the Capsule
share during the preceding 20 trading days.

     4. The amounts loaned by G&A to the Company shall accrue interest from the
date(s) made at the rate of 12% per annum calculated and accrued monthly on the
outstanding balance, and all amounts os loaned, together with accrued interest
thereon, and shall become due and payable upon any questions, merger or sale of
Capsule or the sale of more than 20% of the companies equity to any party by
Capsule.

     5. G&A acknowledges its understanding that any shares of Company common
stock issued to it pursuant to paragraph 3 will constitute "restricted
securities" and will not be eligible for resale unless registered under the
Securities Act of 1933 or unless an exemption from such registration
requirements is applicable, and represents and warrants that it is acquiring any
such shares for its own account without a view to distribution. G&A shall have
the right to demand registration of all the restricted shares which it holds in
Capsule at any time. G&A will agree to pay any legal fees involving such
registration.

     6. The loan may be prepaid at any time without any penalty.

     7. Upon approval from Wells Fargo Business Credit, which the Company will
make its best effort to receive, the Company will assign, pledge, and grant to
G&A a continuing subordinated security interest in the Company's DEX600E Megahub
switch located at 401 North Broad Street in Philadelphia, Pennsylvania and any
other assets which are not now secured to any other lender and in the case of
any asset or assets now secured to other lenders, G&A will be given a security
interest 2nd to the other lenders.

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                              INVESTMENT AGREEMENT

     8. This agreement will be construed under the laws of the state of
Delaware.

                                 Gold & Appel Transfer, S.A.

                                 Signature: /s/ Walt Anderson
                                            ------------------------
                                                Walt Anderson
                                                Gold & Appel Transfer, S.A.

                                 Date: 3/15/01

                                 Capsule Communications, Inc.

                                 Signature:  /s/ David B. Hurwitz
                                          -----------------------------------
                                                 David B. Hurwitz
                                                 President & CEO

                                 Date: 03/20/01

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