How to connect the host unit and guest unit of an intercom controller?

Press and hold the B button on the intercom controller for 15 seconds to enter the secondary menu. At this point, the host unit’s screen displays the word Pairing, and the guest unit’s screen shows the Host Pairing option. Click the B button to confirm and enter pairing mode; on the host unit of the intercom controller, click the A button to select the corresponding guest unit number. If the number is occupied, you can click the C button to go back and reselect a number. If the number is available, click the A button to select Yes, then click the B button to confirm pairing. After a successful pairing, a success message will appear. If a pairing failure message appears, repeat the previous steps. Clicking the C button will return you to the main interface.