Unfortunately, you can't download AVeL Link Server 2.0 because there isn't an online resource available for this purpose. From what it seems, the product is not available for public downloading. I suggest you contact the developers for further information. You can get in touch with them using
+852-2314-1169 (Hong Kong),
+65-6665-4478 (Singapore) phone numbers. If you want, you can visit the English version of I-O Data website.