New Delhi: The Telecom Regulatory Authority of India (TRAI) has begun the phased implementation of the new 1601 series numbering system for service and transactional calls from utility, courier and logistics companies. The series has been created specifically for sectors outside banking, financial services and insurance (BFSI) and government, which currently use the 1600 series for transactional and service calls. TRAI said a separate numbering series was required to prevent important financial and government communications from being mixed with calls from other sectors.