Winlink Express VHF works great with the Icom IC-705 and UZ7HO Soundmodem 1.05 software TNC – you will need the optional CAT/PTT DLL file from UZ7HO website and then set up the Advanced PTT options in Soundmodem to use CAT for PTT. I used the settings for the Icom 7300 – you will have the update/change your IC-705 Connectors Config and the default CI-V address to match the Icom 7300 which is 94h (I used the same setup for WSJT-X). Here is a short setup video:
Since the 705 is still very new in the market (Oct, 2020) It will be important to set the CI-V address under the CONNECTORS configuration on the IC-705 to match the IC-7300 which is 94h and also ensure under MOD Input to set your levels at 50% and then under DATA OFF MOD MIC, USB Here is the whole Connectors settings for reference that worked well with VHF Winlink and soundmodem software TNC. You will also need to set your Icom IC-705 in FM-D (FM Data Mode) for Winlink to work.