NICT Dial-up standard time service (Telephone JJY) is
a system using public telephone line to supply Japan Standard Time (JST)
with high precision. Time signal can be obtained by modem, which is a standard
way for data transmission using a personal computer. The last bit of time
data is synchronized to the rising of the 1pps signal based on JST and
Coordinated Universal Time (UTC). You can obtain the standard time with
+-1 ms precision everywhere in Japan if you use the special receiver on
Introduction of the system is simply explained below:
1.1 Receiving equipment
You can access to this service by any instrument which is available for modem connection, for example a personal computer with modem or a special receiver on the market.
1.2 Starting this service
This system is started by user's equipment or computer ( we call them "user's equipment"). Our transmission devices send the information (such as time code) as the response for the request command from users.
1.3 Outline of the access method
Special communication protocol is not necessary for this system. If you set the parameter as the same way as dial-up connection, you can get the time data by using the commercial communication software. The parameters are shown in the section 2.1. ( Please input the ID number and the password in capital letter in ASCII code, and the command in the alphabet in ASCII code.)
Phone number : +81 423 27 7592
ID : TJJY
Prompt : >
When the prompt is displayed, please input the command "HELP" or "INFO" for the test. You should input the command "BYE" or "END" in order to terminate your access normally.
1.4 Time delay calibration
When the appropriate command is sent from users equipment, our transmitter make the round-trip-circuit, then users can measure the delay time caused by the communication line itself.
1.5 Contact details for inquiries