I bought my clock to hack on but got frustrated with it a have just been using it as a straight-up clock (which it's very good at). Tonight I got an itch to play with it again and decided that an easy entry point would be to try to communicate with it over serial. I'm now almost positive this is where I got frustrated last time.
When plugging in the TTL-232R cable from either a Mac or Linux machine, I don't get a device in /dev to attach to to communicate with the clock. I don't have a windows machine at the moment but I did the last time I tried and I had the same experience there.
It occurred to me that I should probably rule out a bum cable since I've never used this cable for anything else. I used the came cable between the Mac and a raspberry pi and I was able to log in to the pi over the serial console. That's not apples-to-apples since you don't use all 6 pins of the cable in that arrangement, but at least I knew the cable wasn't at a total loss, and confirmed that my Mac _could_ use the cable.
After some more poking around I realized the power pin for J2 is labeled 5V, and that on the wiki page for serial communication with the clock you specifically link to the 5v version of the TTL-232R cable. As it happens I bought the cable I'm attempting to use from adafruit and it is the 3v3 version. I'm very willing to buy a new cable, but I don't want to buy it if this 3v3 cable _should_ work. Do the communication problems I'm having seem likely to be caused by using the 3v3 cable instead of the 5v cable?
Not sure it matters but I assume my clock has the v1 firmware on it since. I haven't touched it in a year or so and it's running whatever shipped on it.
Thanks for your help!