EX-1
from SC 13D
1 page
<page> Exhibits Exhibit No. Description 1 Joint Filing Agreement Dated as of December 20, 2000, by and Between Parent and the Purchaser. <page> Exhibit No. 1 Joint Filing Agreement in Accordance With Rule 13d-1(k) Under the Securities Exchange Act of 1934, as Amended, the Persons Named Below Each Hereby Agrees That the Schedule 13d Filed Herewith and Any Amendments Thereto Relating to the Acquisition of Shares of Common Stock of Detection Systems, Inc. Is Filed Jointly on Behalf of Such Person. Dated: December 20, 2000 Robert Bosch Gmbh By: /S/ Georg Hanen Name: Georg Hanen Title: Senior Vice President By: /S/ Dr. Heiko Carrie Name: Dr. Heiko Carrie Title: Senior Legal Counsel Bosch Security Systems Corporation By: /S/ Gary Saunders Name: Gary Saunders Title: President 13
12/34/56