A new time dissemination service with an accuracy of ± 10 ms over public switched telephone network

A new time dissemination and synchronization service over public switched telephone network (PSTN) has been established at CSIR-NPL. The time synchronization accuracy achieved using is this service is ± 10 ms. The measurement of round trip delay and its cancellation in the final time code sent to the receiver has been implemented in this service. In this paper, the technical details of this service have been described.