Guidance on migration to Table Driven Code Forms

Replacing TAC with TDCF

Procedures

CBS Ext.(2014) considered progress with migration to Table Driven Code forms.

"...the Commission recommended that data providers produce reports in both TAC and BUFR for an overlap period of two months with the intention of completing migration within six months. The Commission asked OPAG-ISS to review progress with migration every six months and to consider whether a further of extension of six months was required to resolve issues with the consistency and quality of data."
(WMO-No. 1140, para 2.3.15)

There are two procedures to support the migration process:

• Managing the introduction of TDCF messages replacing TAC
• Escalation procedure to resolve issues with TDCF messages.

Notifications of starting TDCF bulletins and stopping TAC bulletins

Note 1: These notifications are taken from the Operational Information Service.
Note 2: Members should give as much notice as possible of the dates they intend to start issuing TDCF and cease sending TAC in order that users can prepare their production systems. A minimum of two months overlap is recommended, and suppliers should be prepared to extend the overlap period if users identify issues with how data are represented in the TDCF.
Note 3: The intention of introducing TDCF is to increase the amount of information being exchanged by Members. Members should not stop transmitting information in TAC until all the information in the TAC is being transmitted in TDCF and the relevant GDPFS lead centre for monitoring has confirmed that the data are represented correctly in TAC.

• List of BUFR bulletins that Members have declared as being exchanged on the GTS
• List of TAC bulletins that Members have declared will no longer be sent.