A computer modem works by using phone tones as substitutes for binary code, and the modem receiving these signals translates them back into a usable form. Discover how DSL modems work differently than dial-up modems with help from an IT professional in this free video on computer modems.Expert: Matt Berkowitz Contact: enduserblues.blogspot.com/ Bio: Matt Berkowitz is an IT professional specializing in end-user support for internal networking and hardware-related functions. Filmmaker: Dimitri LaBarge