TDCC provides Taiwan's securities market participants with services including custodian, book entry, dematerialized registration, clearing and settlement, and securities holder list creation. The company adopted BIG-5, which was prevalent in the industry, as the Chinese code for its IT system. However, there were approximately 13,000 BIG-5 standard Chinese characters. In response to participants' needs for rarely used characters, the company offered creation and maintenance services for these rarely used characters. In this way, the securities market was equipped with consistent Chinese character code so that Chinese data could be presented entirely and accurately during data exchange. Nevertheless, the maximum capacity for BIG-5 rare character creation was only 5000 characters. Over the past three decades, the capacity had already been far from sufficient.

To resolve the inadequacy of rare character creation once and for all, TDCC referred to the trends of IT system construction in government institutes and market information development. The company organized "Securities Market Chinese Code Changeover Operation125 with the support and approval of the competent authority. In participants' systems and TDCC's own corporate system, TDCC changed the Chinese code in the exchanged materials from BIG-5 to the international standard Unicode. The company aimed to meet the national word bank standard, expand Chinese code capacity, standardize fonts and data exchange, and improve the efficiency and accuracy of data exchange in the securities market.

The influence of the Chinese code changeover operation was extensive. The inventory showed 181 files contained Chinese from the data exchanged with participants. The scope of the changeover covered more than 30 systems, including the core accounting system, the front-end system connecting to participants, and peripheral systems. To reduce the risks in the project, TDCC's internal experts conducted the changeover in phases. First, in 2018, they initiated a "leading project for key technology of Chinese code,125 developing and verifying each key technology for Chinese code changeover and establishing a standard procedure for the code changeover program. In November 2019, the "Chinese Code Changeover Project125 was activated, and planning, development, and testing were conducted.

For the purpose of supporting Unicode changeover data processing, thousands of programs and procedures in TDCC's core accounting system needed to be converted, and more than thirty relevant information system functions required adjustment. After IT members completed program development and integration testing, they invited the business department to conduct quality verification. Plenty of testing, such as business day testing and typhoon holiday testing was completed, and the testing was categorized into daily business, weekly business, and monthly business. Testing items included online transactions, full batch operation, and peripheral system data exchange to ensure system quality was up to go-live standards.

During the Chinese code changeover process, in addition to the necessary modification of TDCC's IT system, securities-related participants' internal interface data systems also needed adjustment. To allow participants sufficient time to conduct relevant system development and testing, TDCC held many orientations for participants in September 2020. All market participants were invited to communicate and discuss the influence scale and provisions face to face. From December 2020, the company provided the Unicode version of business day testing environment for participants and put a testing model on the company website for download, so all market participants could verify Unicode version's specifications of sent and received files. At the initial stage of the project, most participants were still looking for solutions, so the progress was slow. To encourage participants to speed up the modification and testing, TDCC created the "Chinse Code Changeover Testing Incentive,125 instilling momentum into the project. The event received enthusiastic participation, and the pleasure from competing for project completion was thus created. TDCC's projects members made every effort to contact participants in the whole market, confirmed the testing progress one by one, and ensured all of them had completed development and testing operations without any detail omitted.

There was another arduous task in response to the Chinese code changeover: the overall program update of all workstations processing all participants' TDCC book-entry. In the first half of 2021, TDCC entrusted IT vendors with Unicode software installation and setting in participants' workstations throughout over 1,000 business locations. The total number of workstations with complete installation was 3,100.

In 2021, regardless of the disturbance of COVID-19, participants and TDCC completed IT system development and testing on schedule, and the project entered the intensive preparation stage for the system go-live. To ensure the securities market's clearing and settlement, book-entry, and shareholder services ran smoothly after the changeover went live, TDCC held two holiday market testing drills in September 2021. The company invited all participants to a situational exercise of a previous day's operation. The operation included each report, calculation, auditing, and relevant book-entry business such as the execution, clearing and settlement, errors of accounts and default, and category change. The official Chinese code changeover go-live required more than 300 participants in the whole market and TDCC to conduct a simultaneous IT system update, so this transition was enormous. To ensure the complete system update, a connectivity test with the market was conducted one day before the system went live. In this test, the number of market participants calculated by headquarters and branch offices reached a total of 1,124.

The operation of Chinese code changeover took three years; with the supervision of the Securities and Futures Bureau of FSC and the cooperation of all the market participants, it finally went live on October 18, 2021. Since then, the system has been operating smoothly, and each process has been completed as planned. TDCC will continue incorporating innovative technology into information management skills, strengthen their core competitiveness in response to market development, develop more diversified business, and provide the best quality services for the market.