UMCM: Cutting International Call Costs with SIP
I built an intelligent callback engine that routes calls through the cheapest carriers via SIP trunks. Used by DSV, Impregilo, and Ferrero.
International calls were expensive. UMCM was my answer to that: an intelligent callback engine that could be installed on-premise or run as a cloud service. The system automatically routed outbound calls through whichever SIP trunk carrier offered the cheapest rate for that specific destination.
How it worked
The core was a phone number rewriting system. End users dialed numbers exactly as they normally would. UMCM intercepted the call, looked up the destination, checked current rates across all configured SIP trunk carriers, and routed the call through the cheapest available path. The caller never noticed anything different. The phone bill did.
The callback mechanism was the key. Instead of placing a direct international call at premium rates, UMCM would drop the initial call and call the user back through the cheapest route, then bridge them to their destination. Transparent to the user, significant savings on the invoice.
Customers
The system found its way into some notable companies:
DSV - the Danish logistics giant needed cheap international calls across their global operations
Impregilo in Italy - one of the largest construction companies in Europe at the time
Ferrero in Italy - yes, the company that makes Nutella
Beyond the large installations, there were smaller setups and pure cloud solutions for companies that didn't want on-premise hardware.
Why it ended
International roaming and calling costs dropped. Mobile carriers started offering flat-rate international packages. The price gap that made UMCM valuable shrank until the savings no longer justified the complexity of running a callback engine.
I shut it down. The market solved the problem I was solving, which is the best and most frustrating way to lose a product.
What it taught me
UMCM was an early lesson in building infrastructure that solves a real, measurable cost problem. The value proposition was simple: your phone bill gets smaller. No abstract benefits, no "improved workflows." Just money saved. That clarity of purpose is something I try to carry into every project since.