1 EXHIBIT 15 UNAUDITED INTERIM FINANCIAL INFORMATION LETTER Securities and Exchange Commission 450 Fifth Street N.W. Washington, D.C. 20549 Commissioners: We are aware that our report dated January 18, 2000 on our reviews of interim condensed consolidated financial information of Digi International Inc. and subsidiaries (the Company) for the three month periods ended December 31, 1999 and 1998, and included in the Company's Form 10-Q for the quarter ended December 31, 1999, is incorporated by reference in the Company's registration statements on Form S-8 (Registration Nos. 33-32956, 33-38898, 333-99, 333-1821, 333-23857 and 333-57869). PRICEWATERHOUSECOOPERS LLP Minneapolis, Minnesota February 11, 2000