Graphic depicts a big box representing Online Mediation Controller. Inside the Online Mediation Controller box from top to bottom are Balance Manager Service and Balance Manager Web Service connected by two-way arrows. The Balance Manager Web Service is connected by two-way arrows labeled "WS Requests" to SMS, IVR and WEB boxes outside the Online Mediation Controller box; these represent the external interfaces.
The Balance Manager Service is connected by two-way arrows outside the Online Mediation Controller box to an oval representing the OCS (BRM or ECE), which itself is connected to two databases: Subscriber DB and Voucher DB.