Live TV Pause is a feature that allows you to pause up to 90 minutes of live television.
How does it work?
Live TV Pause is only available on the Antenna TV input of your Roku TV™ and requires a dedicated USB 2.0 compatible flash drive with at least 16GB of storage for recording the video.
To pause live television, press the Play/Pause button 
on your Roku TV remote control. Even if you do not pause, you can rewind the current channel up to 90 minutes, or to the point where you first tuned to that channel. As soon as you tune to another channel, power off the TV, or leave the Antenna TV input, the place where you paused the program will be lost.
After being paused for 90 minutes, playback begins automatically.