New inexpensive frequency calibration service from NIST

An extremely cost-effective, modest-accuracy method of remotely obtaining time and frequency via a telephone model is demonstrated. This method uses the operation of the National Institute of Standards and Technology´s (NIST) Automated Computer Time System (ACTS), which was begun in 1988. Time and frequency dissemination by this service depends on the reciprocity of the telephone system. The round-trip delay is measured by the NIST equipment. The advance of an on-time marker is adjusted so as to arrive at the user´s site on time. A frequency calibration method taking advantage of this service, and preliminary tests are discussed. A computer is not required to access this service. All that is required is a telephone modem, a simple peripheral circuit to generator an on time marker and standard time and frequency measurement and data processing equipment