OTE documented PTT-era billing and provisioning logic to anchor a Cosmote-converged platform refresh.

OTE Group, the Hellenic Telecommunications Organization, has been Greece's incumbent telco since 1949 and now operates fixed, mobile, broadband and TV services under the OTE and Cosmote brands. Decades of PTT-era infrastructure left a substantial COBOL estate beneath provisioning, mediation, billing and settlement — the systems that hold the Greek market's revenue together but had grown opaque to all but a handful of long-serving engineers.

COBOLpro extracted the production logic from source and rebuilt it into a navigable reference: provisioning chains across fixed-line and mobile, mediation handoffs between Cosmote network elements and central billing, the rating engines that price each tariff family, and the batch settlement chains that close the day. Each was validated in structured sessions with the original engineers, capturing the operational scenarios — number portability, prepaid-to-postpaid migrations, irregular billing windows — that drive change traffic.

The reviewed reference now anchors OTE's Cosmote-converged platform refresh. Programme leadership uses it to sequence retirements, migrations and rewrites; change teams use it for impact analysis before touching production billing or activation paths; and new engineers joining the Athens estate have a documented onboarding artefact instead of the years of shadowing that knowledge transfer used to require.