I follow the instructions on your YouTube channel for pairing the TS1s, but they don’t work.
What is the firmware version of your GC2 alarm panel and what is the firmware version of the TS1s? The GC2 will need to have the appropriate matching firmware version to communicate with TS1s. You can find the firmware of the GC2 by following this video.
Do you have an XCVR2 installed in your alarm panel? This is required for TS1 communication. It replaces the transceiver that comes with the GC2 panel
I reset the TS1s to factory defaults and was then able to pair.