Supplement 2 to Recommendation ITU-T D.195 is intended to assist telecommunication operators interested in developing guidelines for day sales outstanding (DSO) management. Since an operator's decision to establish prepayment mechanisms is an internal commercial matter (with terms negotiated between operators), the guidelines in the present supplement are voluntary and meant to be illustrative in nature. Their objective is to help operators formulate new (or update existing) DSO guidelines according to their own needs, business strategy and headcount pressures.