The Federal Signal 2001 Series is a line of outdoor warning sirens produced by Federal Signal. Variations include the 2001SRN, 2001SRNB, 2001-130, and the Equinox.
The 2001SRN siren began production in 1988, replacing the Thunderbolt with a much less complex, and thus more reliable, design. It also introduced battery backup. This model is identifiable from its successors by the large, rectangular rotator box design borrowed from the Thunderbolt Series as well as the "2001DC" label on the rotator. This series came in two forms, the early "Roundback" and the later "Squareback", referring to the shape of the rear housing. Roundback models were only produced for a short time and much less common than the Squareback variant, with a few of the known Roundback sirens being located in Angola, Indiana; Fostoria, Ohio; Romeoville, Illinois, Southaven, Mississippi; Wichita, Kansas; Noblesville, IN; and Prior Lake, Minnesota. Aside from the rear housing, the two variations are identical. The original 2001-SRNs made from 1988-1998 had small motor covers, however in 1998 a newer 2001-SRN with a larger motor cover and small Federal Signal logo stuck on it
The 2001SRNB was the second generation of Federal Signal's 2001 series. The design is similar to its predecessor, the 2001SRN, with the most notable change being a refined stator design, increasing the sound output to 128 dBc at 100 feet. Secondly, bringing the belt-less, cube shaped rotator originally inherited from the Thunderbolt back in 1993. The earlier models made from 2003-2005 had a small Federal Signal logo, however in 2005 a larger logo was added on to the siren.
The 2001-130 is a version of Federal Signal's 2001 Series, with production starting in 2006. A support beam, which previously ran across the intake and restricted airflow, was relocated. The rear housing was also made taller, raising the intake above the collector ring assembly. This model can be identified by the 2001-130 label on the rotator housing as well as the increased rear housing height.
The 2001 Eqiunox is the latest version of Federal Signal's 2001 Series, with production beginning in 2011. It was originally made as a prototype for the 508 siren. See Federal Signal Equinox for more details.
The current controllers that Federal Signal sells to operate the siren are the DCFCB and 2001-AC which are used for 120VAC power and 208 or 220/240VAC respectively. Both controllers have NEMA 4X aluminum cabinets with 2 48VDC chargers. 2001DC used to be the name used for the DC controller sold for the siren and is where the nickname for the 2nd gen -SRNs (the ones with the 2001-DC sticker) came from.