Alerting Communicators of America was a company formed in 1967, after its parent company, Biersach & Niedermeyer, left the siren business. ACA produced many popular sirens such as the Allertor 125 and the Penetrator series, but ACA faced major financial troubles and poor decision making in the mid 1990s, causing it to go out of business in 1994. ACA would be bought by Hörmann, and reformed into the American Signal Corporation, which is still in business today, although they are no longer owned by Hörmann as of 1998.