It is now clear to me, and I agree with others, that the Rosenthal FDCPA applies to the original creditor. California Civil Code 1788.2 (c) says:
(c) The term “debt collector” means any person who, in the
ordinary course of business, regularly, on behalf of himself or
herself or others, engages in debt collection. The term includes any
person who composes and sells, or offers to compose and sell, forms,
letters, and other collection media used or intended to be used for
debt collection, but does not include an attorney or counselor at
So, if you start getting collection letters from anyone, including the creditor, and you live in California, you should check with an attorney to see if there are any FDCPA violations.