LSI/CSI LS7501-7510 U ® L LSI Computer System.
LSI
LS7505 - TONE ACTIVATED TELEPHONE LINE SWITCH CONTROLLERS
LSI/CSI LS7501-7510 U ® L LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (516) 271-0400 FAX (516) 271-0405 A3800 TONE ACT.