ABOUT 350 delegates are expected to attend EDI Asia '93 to be held between September 27 and 30 at the Hong Kong Convention and Exhibition Centre. The event, which is organised by Tradelink under the banner of the Hong Kong Council for Simplified Trade and EDI (STEDI), will include elements to help delegates prepare for the EDI-based community electronic trading service (CETS) which is expected to be implemented in the next few years. ''EDI Asia '93 has a balanced range of courses,'' said Juletta Broomfield, general manager of Tradelink. ''A delegate who knows nothing or little about EDI could start with the basic Introduction to EDI. Delegates also could mix and match courses to suit their specific needs, she said. Speakers at the event include Peter Hudson, director of Electronic Trading Concepts, Australia; Benjamin Wright, a US lawyer; Patrick Li, managing director of SKL Technology, an EDI consulting firm; and Graeme Hopgood, director of Coopers & Lybrand.