An innovative time service via telephone network - A study on its potentiality

National Physical Laboratory, New Delhi, India (NPLI) has started a new time service by transmitting digital time data via telephone network in name of Teleclock service which is quite different from the usual dial-up time service. Data for the time of the day are sent five times for the sake of redundancy. The phase information related to the second pulse is also disseminated, thus providing the provision of delay compensation. NPLI has also developed a Teleclock receiver to access this time service. Receivers have been designed to access this service either via landline network or mobile network. Real Time Clock of the receiver is set/synchronized with the received time data. The confidence in accessing correct data has been worked out. The accuracy of time signal has been studied for both landline and mobile network. The accuracy of the order of sub millisecond has been observed. Online delay compensation has been planned. Transmission system for commissioning such time service is inexpensive and simple. Further, the cost of the receiver is affordable and mainly depends on the size of the display. So this system opens up an opportunity of staring a national time service and thus is gaining popularity in many developing countries. This paper describes the system configuration, emphasizes the important features of this system and elaborates the uniqueness of this time service.