PLDT documented seven decades of fixed-line and Smart-mobile billing logic for a digital-services modernization.

PLDT, the Philippine Long Distance Telephone Company, has anchored Philippine telecommunications since 1928 and today operates fixed-line, enterprise, fibre-broadband and — through subsidiary Smart Communications — the largest mobile network in the country. Roughly seven decades of accumulated COBOL workloads sit beneath provisioning, mediation, billing and settlement across this footprint, with engineering knowledge concentrated in a small group of veterans.

COBOLpro captured the legacy fixed-line billing chains, the Smart-side rating and mediation rules, and the cross-system batch settlement that links them — under heavy load from more than 70 million subscriber relationships. Outputs were validated by the original engineers in review sessions, including the corner cases that only show up at the scale of the Filipino mobile market and the regulatory specifics PLDT operates under.

The reviewed package gave PLDT's modernization team a deterministic reference for sequencing the move toward digital-services and converged charging: which rules transfer cleanly, which require rewrites, and which rest on legacy assumptions that no longer hold. The same artefact is now the on-boarding reference for engineers joining the rating and billing estate during the migration.