1 Exhibit 10.23 PROMISSORY NOTE - ------------------------------------------------------------------------------- Borrower: Stephen M. Tennis Lender: Verilink Corporation 199 Hillside Avenue 145 Baytech Drive Menlo Park, CA 94025 San Jose, CA 95134 - ------------------------------------------------------------------------------- Principal Amount: $20,000.00 Interest Rate: 6% Date of Note: June 4, 1997 FOR VALUE RECEIVED, Stephen M. Tennis ("Borrower") promises to pay to Verilink Corporation ("Verilink"), or order, in lawful money of the United States of America, the principal amount of Twenty Thousand Dollars and No Cents ($20,000.00) or so much as may be outstanding, together with interest on the unpaid outstanding principal balance from the above date until repayment of the principal and interest. Payment is due in full on demand of Verilink. In addition to payment of principal, Borrower also agrees to pay interest on the aggregate unpaid principal at a rate equal to Six Percent (6%) per annum. Borrower may prepay all or any part of the amount due hereunder without penalty. If any costs, expenses and attorneys' fees are paid or incurred, or adjudged by a court in any action to enforce payment of this Note or any part of it, the prevailing party shall recover from the other party such costs, expenses and attorneys' fees. Borrower waives presentment, demand, protest, notice of protest, notice of dishonor, notice on nonpayment, and any and all other notices and demands in connection with the delivery, acceptance, performance, default or enforcement of this Note. This Note shall be deemed to be made under and shall be construed in accordance with, and governed by, the laws of the State of California. Borrower: /s/ STEPHEN M. TENNIS ------------------------ Stephen M. Tennis