So have had the APRS PRO application on my iphone for a while, but would like to take advantage of it more often for HR APRS. Have a line splitter that can attach to the earphone port and separate the microphone and the speaker. Should I be able to run APRS HF doing this? Assuming that I adjust the levels of the audio signals into and out of the HF radio, and the cellphone? Also assuming the HF radio has VOX. Has anyone done this? When looking at the various videos for this application, it looks like they just use sound coupling, with no audio cables.