1. All appeals filed by the Plaintiff (Counterclaim Defendant) against the instant principal lawsuit and counterclaim are dismissed.

2. The costs of appeal shall be the principal lawsuit.

1. The reasons why the court of first instance should explain this case as to this case is the additional evidence submitted by this court and rejected the testimony of Gap evidence Nos. 10, 11, 12, and 18 (including paper numbers) and witness F of the trial party who are insufficient to recognize the plaintiff's assertion. Except for the addition of the judgment on the plaintiff's assertion in this court as follows, the court of first instance shall accept this case by applying the main text of Article 420 of the Civil Procedure Act.

2. Additional matters to be determined;

A. Since the Plaintiff’s assertion reached an agreement with D on January 18, 2016 on the instant supply contract, the Plaintiff did not have an obligation to perform the obligations under the instant siren contract.

B. Each description of Gap evidence Nos. 6, 7, and 8 and witness F’s testimony regarding the fact that the conclusion that the instant supply contract was agreed upon is difficult to believe, and there is no other evidence to acknowledge it.

Even if the Plaintiff terminated the instant supply contract, it cannot be deemed that the instant siren contract naturally loses its validity in light of the form and content of the contract, unless the Plaintiff notified the Defendant of the withdrawal or termination of the instant siren contract.

The plaintiff's above assertion is without merit.

Even if the Plaintiff did not have been installed from D in the instant sirens contract, the Plaintiff signed and sealed a copy of the certificate of acceptance of the sirens product at the time of the completion of the receipt and installation of the sirens product, and then delivered one copy of the certificate to the Defendant Company on January 4, 2016 under the instant sirens contract (Article 2(4) of the certificate No. 3 and Article 2(4) of the same Act (Article 2(4) of the certificate No. 3). The Plaintiff signed and sealed as one contractor in the “written confirmation of acceptance (installations) and other notification” column of the instant sirens contract, and the Plaintiff signed and sealed as one contractor’s name on January 4, 2016.