If the cable box is paired to a cable remote via RF, it will not respond to IR commands. You must reset the RF pairing by factory resetting the remote.
For what its worth, I integrated a 201-H box at a customers house last week. Here's how:
Factory Reset & Unpairing
If you’re having trouble with your remote, and no other troubleshooting steps have worked, you may want to reset your remote to its out-of-the-box settings, or unpair it from your TV and try again.
To perform a factory reset:
Press and hold the Menu + OK buttons until the Input button flashes twice.
Press 9 8 1.
The remote should now be reset.
To unpair your remote:
Press and hold the Menu + 3 buttons until the Input button flashes twice.
The remote should now be unpaired.
After I did this the box responded to IR commands using a scientific Atlantic driver
Instructions found at
You can find the IR receiver by shining a light down from the top of the box.