I have checked out your suggestion, Lyndel, and I believe that an IR Extender and IR Receiver is what I do need, but (you might say) in "reverse order".
Here's why I say that.
I found a "Wireless Dual Band IR Remote Control" on the web
As I understand the write-up (and the video), one of the units (let's call it Unit 1) receives an IR signal, converts it to an RF signal, and then sends that RF signal to the second unit (call it Unit 2) that then converts the RF signal it received back to an IR signal, and passes that IR signal on to the box that is controlled by the IR signal.
If that is correct, then can I "teach" the ProntoPro the proper IR commands by using Unit 2 to convert the RF signal from the new remote control from Comcast into an IR signal?
And then, could I place Unit 1 somewhere in line-of-sight of the ProntoPro so that when I press a key, hard or soft, on the ProntoPro and send an IR command to Unit 1, it will convert it to an RF signal and send it to the new DVR box from Comcast?
I hope what I am saying here is clear and that you can answer my question.
Thank you very much!!