CalConnect DATETIME Technical Committee


Since its inception CalConnect has established at least five Technical Committees and Ad Hoc Committees to work on some aspect of date/time notation and management, including formats, time zones, daylight saving time, recurrences, and so forth. Each time the committee has completed its scope of work and been closed, a new one was needed relatively soon thereafter.

CalConnect is now working closely with ISO/TC 154/WG 5 on date/time related matters and will be holding Convenership of that workgroup. Therefore, CalConnect has resolved to establish a new standing Technical Committee to cover all aspects of date/time issues and management going forward, and to manage the liaison relationship with the appropriate ISO TCs.


TC-DATETIME is the home for all date and time related work undertaken in CalConnect and between CalConnect and external liaison organizations, such as ISO Technical Committees.

TC-DATETIME aims to provide a common platform for all date and time stakeholders, to enable a unified, interoperable understanding of date and time across populations and systems.

Specifically, the scope of work of TC-DATETIME includes the standardization of:

  1. Concepts and semantics related to date and time
  2. Systems and processes that use or measure date and time
  3. Interoperability of digital systems that utilize date and time

In addition, TC-DATETIME is tasked with supporting other CalConnect TCs on matters that involve date and time concerns. Where work in another CalConnect TC involves issues covered within the scope of TC-DATETIME, the work should be done within TC-DATETIME, or in form of a joint working group with TC-DATETIME, unless the Technical Coordination Committee decides to leave the work in the originating TC.

TC-DATETIME is also tasked with maintaining the liaison relationships with external liaison organizations on work within its scope.

Initially the TC will inherit the work undertaken by the Ad Hoc Committee on EU Time, which was established at CalConnect XLIII to develop an Advisory Report on the EU Summer Time Proposal, and will include follow-on activities such as the planned Time Zone Workshop at CalConnect XLIV in February 2019. The TC will also inherit the established liaison relationship with the date/time work being undertaken in ISO/TC 154 and be responsible for managing and reporting on CalConnect liaison activities with that TC.


  • Final published version of the Advisory Report on the EU Summer Time Proposal
  • Distributing and publicizing the Advisory Report to targeted decision makers in the EU and to selected press entities and journalists
  • Developing and conducting the Time Zone Workshop at CalConnect XLIV
  • Reporting on the workshop including outcomes and further work
  • Publishing and publicizing the results of the workshop
  • Periodic reports on liaison activities with ISO/TC 154
  • Establishing, conducting and reporting on CalConnect positions on outstanding ballot items in ISO/TC 154 relevant to the TC’s scope and mandate

Begin and End Dates

  • Begin: October 2018
  • End: Standing Committee

Milestones and Work Products

| Period | Milestone | | — | — | see above

DATETIME Mailing List

You must be an employee of a CalConnect member to be subscribed to this mailing list except as approved by the TCC (e.g. representatives of liaison organizations). You must be subscribed to this mailing list to post messages.


Participation on the TC-DATETIME mailing list will be in accordance with standard CalConnect practices and procedures.


Dave Thewlis, CalConnect ( (Pro Tempore)

Ronald Tse, Ribose (

Please contact the Chairs for more information or to join this Technical Committee.

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