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Japan Standard Time Group

Integration of time dissemination (services) via networks into NTP

- Approach to the end of “time dissemination service using http/https protocol” -

NICT not only generates Japan Standard Time but also disseminates it in various ways such as long wave, telephone JJY, hikari-telephone JJY and NTP.
Though we have been providing a trial service of time dissemination using http/https protocol besides NTP, we have decided our policy to integrate the two dissemination services and start [procedures] towards the termination of “time dissemination service using http/https protocol.”[The reason for unification is detailed below.]
We ask for your kind understanding and cooperation about the following impacts listed below that may occur on some users according to the procedures.

Possible impacts of the temporary break of the service

Temporary break schedule

No impact on the following

✔ Most smartphone and PC apps which do not use NICT “time dissemination service via http/https protocol”
✔ Your computers and the following pages that shows the time difference of your PC with respect to the standard time. (see the figure below)



✔ Our NTP* service will be operated as usual.
*NTP: A network protocol used to synchronize computers or various apparatus with a clock to a standard time.

Some impacts may appear on the following

✔ Some smartphone apps, PC software and hardware which acquire time information via NICT "Time dissemination service using http/https protocol"

There will be some slots which NICT breaks the operation of "Time dissemination service using http/https protocol"(see the figure below)


Contact us

Mail address:


The reason for the integration

The reason for the integration of network-based time dissemination services is as follows. We would appreciate your consideration.
"Time dissemination service using http/https protocol" was a trial developed for some limited users who couldn't reach NTP services owing to the firewall.
Recently however, time dissemination using NTP has become common on the internet and is available to the most users.
On the other hand, the number of access to the current system of time dissemination service using “http/https” increased rapidly around from 2016 even though it was established as just a trial service. In the latter half of 2018, temporary break due to excessive access occurred.
Considering the limited budget and staff, it will be in a difficult situation in the future to maintain two services by preparing increasing number of server and by expanding capacity of the line to internet.
Also, we are concerned that further increase of access may cause a sudden stop and bring users significant damages if the service is continued with insufficient capability. Prompt action such as termination of the service is considered.
Therefore, this integration of the service to NTP is a step to strengthen the reliability of time dissemination.

Procedures towards the termination of “time dissemination service using http/https protocol”

As procedures towards the end of “time dissemination service using http/https protocol,” we will take the following two actions at the same time.

Gradual restriction as a notification to the end users.
We cannot make direct contact with each user of "Time dissemination service using http/https protocol" Accordingly, we will perform gradual restriction to notify all the users about the possible termination of service in the future. (Length of break will be extended gradually.)
Please confirm in the Notice of temporary break
Regardless of this process, unexpected service disruption may occur due to excessive access to the server.

The source code of the "time distribution using http/https" service will be available if you apply for it at the contact address.
Users can build the original servers by using this program.
※It should be adjusted for the user’s individual environment.
※When necessary, we will provide technical assistance to establish HTTP time dissemination server. (fee-charging is assumed)