I am using the visual port which uses the internal diagonal.
I bought the 25' version of this cable...
...and it worked great!
I just came in from a very successful evening of EAA observing using my ETX-80/RI2. I started at Altair, hopped southwards across Scutum and Saggitarius, then across Capricorn, Aquarius, and Pegasus, ending the evening at M33 in Triangulum. I located dozens of deepsky objects, only coming up empty on maybe 3 targets. I synched the mount on each object before moving on to the next and I only had to use the eyepiece on 3 occassions when I had to slew a long distance. Each time the object was within the field of the eyepice, but out of the field of the camera and it was easy to get it centered and to continue.
Overall, this system easily outperforms my 16" as far as what you can see, but of cours the view through the 16" is a very different experience so the two compliment each other nicely.
The ETX is a solid performer, but as I have cautioned above it takes a light touch and a bit of patience. Slow slew speeds (a setting of 3, 8x sidereal) and frequent synching helps to settle it down. You also need to fiddle with the camera settings to find what works. I spent most of the night in monochrome mode, with an exposure of 256 (about 5 seconds) and an AGC of 24. The color mode worked great on nebula like M8, 16, 17, and 20. For most other targets, including galaxies, I prefered the monochrome mode.
Soooo, it all seems to work as it is supposed to. The drives on the ETX really aren't up to the task of imaging, but they work well with the RI2. The RI2 is simple, effective, and very sensitive.