Our ARES group decided to pursue a group building project to make Sound Card Interfaces for use with Winlink on 2m. N4OFA suggested the KH6TY interface which was published in QST Magazine last June. We assembled all the parts and met on Saturday, February 27, to assemble the kits. I got mine working fine, but the circuit requires a supply voltage and my FT-817 transceiver doesn’t provide one on the Data Port. So I strapped a 9V battery on the side of the interface.
I wasn’t satisfied with the battery powered interface and looked for alternatives and found this one from VK2ZAY: http://www.vk2zay.net/article/161 I had to order the transformer from Mouser (42TM021-RC), but I had all the other parts on-hand. I just got this assembled and tested today, and it works very well. Here is the schematic that I used: VK2ZAY