This is what I find on the internet:
Biscuit (Belgian, Dingemans) seems to be "fully toasted, lightly roasted" around 350F, resulting in 18-27
degrees Lovibond, and containing no enzymes (must be mashed). It does not appear to be stewed, i.e., a crystal/caramel malt. Some say "Saltine Crackers" character and adds amber color to the beer.
Victory (USA, Briess) seems to be lightly roasted, resulting in 25-28
degrees Lovibond, and contains no enzymes (must be mashed). Some say similar to Biscuit but "nuttier in character" and capable of adding orange highlights to the beer.http://northernbrewer.blogspot.com/2010/07/ingredient-showcase-biscuit-malt.html
Amber malt (UK, Fawcett) is a more "strongly toasted, slightly roasted" form of pale malt, kilned at temperatures of 150-160 °C, resulting in 30-42
degrees Lovibond (22 SRM). and containing no (or very low) enzymes (must be mashed). Amber malt has an intense, bitter "roasty" or "dry toffee" flavor which mellows on aging. Helps to balance with crystal and caramel malts. Low grain bill percentages (2-5% max) recommended due to intensity and color contributions.