An electronic security seal (e-Seal) is disclosed. The e-Seal monitors security of shipments including intermodal containers, reports tampers in real-time, monitors environmental status of goods and reports exceptions in real-time, and reports the location of the shipment with high frequency. The security monitoring complies with the ISO 17712 standard, adding electronic real-time reporting of tamper time and location and LED tamper indication. The e-Seal can be manufactured and operated at low cost due to diagnostic and logistic features. The e-Seal supports low cost upgrades due to a modular architecture allowing a plug-in update of separate functions. The e-Seal allows flexible usage across supply chain tradelanes, due to highly programmable operation including over-the-air remote programming via wireless communications. The e-Seal provides low power operation to save battery usage and lower costs.