I assume you have already done a proper Forum Search for your model number in case other people have already answered your question ?
If so and that didn't help then check out this thread: https://community.sling.com/thread/3300?tstart=0
Come back if it that doesn't help either.
I am afraid to try anything with a slingbox unless someone has actually done it already.
I have had this slingbox since 2007.
I have also worked with my daughter's slingbox and two friend's slingboxes.
Any time I do anything with any of them it becomes a real mess. Things keep going downhill. I go through a process and it fails. I try again, it takes me through a different path and fails again.
Same thing with "firmware updates". Do one and I'm in for hours of fail, repeat, fail, repeat, fail, repeat.
So, once I know that a real customer has actually made their Pro work with a Cisco DTA 170, it is hands off for me.