Hi Brenton, that screen cast helps a bunch! screen did briefly flash an error message at the bottom complaining that /dev/cu.usbserial couldn't be found, so that suggests that you don't have the Prolific serial driver installed which is a necessary step. You can download it from
here, make sure you grab the 1.6.0 version as that's the one you need for El Capitan[*]. It's generally best to install these types of drivers with the device NOT attached, and then attach it once the install is finished (a driver like this should not require a reboot of the Mac, though their installer may ask you to do it anyhow, if it does then let it do the reboot).
Once you do this when the cable is attached the /dev/cu.usbserial node should be present. You can type "ls -l /dev/cu.usbserial" in the Terminal window to confirm, if it still says no such file it would help to do a "ls -l /dev/cu.*" and see what it comes back with, generally Prolific's driver has used that name when a single device is attached, it gets more creative when a second device is attached since each one has to have a unique name to access it. Note that it will only exist when the cable is attached, things in /dev/ come and go as the devices come and go.
[*] As a total aside and purely FYI (since I heard "El Captain" in the video), it's El Cap
i tan, pronounced more like "L cah-pee-tawn". It's a Spanish name (though it is Spanish for "The Captain"), and in Spanish A's are pronounced soft, like the A in "palm", and I's are pronounced like E in English, in fact reading the Spanish vowels A-E-I-O-U sounds like "Ah-A-E-O-Ooo", but at least in Spanish words are pronounced just like they're spelled (and vice-versa), nowhere near the goofy rules/exceptions English has ("I before E except after C? That's
weird!"
). There's also an accent on the final "a" that changes its sound a bit (it's technically "El Capitán", so that last syllable is more like "lawn" in English). It's a famous rock formation within Yosemite National Park. Amazing place, and I got a particularly good introduction to the park the first time I visited, as I came in after dark to stay in a village within the park, so I saw nothing but trees on a windy road when I came in, and stepped out of my cottage the next morning to find that I was deep in a valley surrounded by gigantic rock walls. That was pretty awesome. :jaw: Now it seems a bit odd to me that the OS name shifted from the entire park (Yosemite, 10.10) to a single formation within the same park (El Capitan, 10.11). I don't quite get it, maybe it was meant to suggest a more focused update, like Lion->Mountain Lion or Leopard->Snow Leopard. Mavericks (10.9) has nothing to do with Yosemite other than also being in California.