Not sure, but wanted to toss out there's apparently a github project that does USB Control for at least some Alphas. [0]. In the case of USB type things, it's

Not sure, but wanted to toss out there's apparently a github project that does USB Control for at least some Alphas. [0]. In the case of USB type things, it's probably a bit easier to 'sniff' traffic and reverse engineer the protocol if one wants to. And while some MFGs are notorious for being 'protective' around their protocols (i.e. lenses) I think remote controls are likely not as much a bread and butter to them, so there's less incentive (especially without obsoleting a lot of existing kit.) [0] - https://github.com/pixeltris/SonyAlphaUSB https://github.com/pixeltris/SonyAlphaUSB