This DStv B8 remote has three modes and can be set to TV1, TV2 or TV3 mode. The default mode is TV1. You will see a green light blink every time you press a button on the remote control.
If you have multiple decoders in your home or even in the same room, you need to set the remotes (and the decoders) to different “modes”, so that the commands sent from one remote, won’t be picked up by the other decoder. If you are using two DStv HD Decoders, you will need to set one remote to TV1 mode (to operate the first decoder) and another remote to TV2 mode (to operate the second decoder).