Billing was historically used to refer to the information provided to postpaid customers; charging to the balance management process used for prepaid customers; invoicing the process used to provide information to business customers. However, all three of these processes can be referred to as ‘billing’ in a more generic sense.

To create a bill requires three basic steps (each of which have a number of sub-processes): 1. collection and mediation of usage data; 2. calculation and generation of the bill; 3. presentment of the bill in a format the customer can use. After this process there is a financial process of payment collection, reconciliation and debt management.

Many billing systems now claim to be convergent. Convergence in this sense can mean the billing engine works across multiple technologies (mobile, broadband, fixed line, 2G, 3G, 4G, 5G etc), or that it can

handle both prepaid, postpaid and paynow methods of payment, or both. Some billing systems are effectively built from scratch or from a core system by systems integrators or billing vendors (custom built or bespoke); others are products that are implemented on-premise and may be customised to a greater or lesser extent; some are cloud-based SaaS products which are usually far less customisable.

Most large telecoms operators have multiple billing systems with each billing for a different technology type, product or group of customers. Consolidation of these systems via digital transformation is a key theme but is expensive, can be risky and takes considerable time to achieve. Full consolidation is rare because telecoms firms often engage in M&A and new systems are acquired along with the networks and customers they support.