Tally lamps can recieve the tally signal transmitted from a video switcher with up to a 200m (line-of-sight) distance. The AVMATRIX TS3019-4 wireless tally system supports both 433Mhz wireless and RS-485 wired connection with long and stable signal transmission High Compatibility The tally box supports various interfaces such as GPIO/USB/RS-232/RS-485, which can be compatible with Vmix video switchers. The interfaces can meet users' different needs and applications. Intuitive Status Display The tally system supports up to 16 tally lamps. There are both front and rear indicator lights on the tally lamps with 4-level brightness that can be adjusted. Users can also check signal strength and power statuses easily Dual Power Supply The tally lamp can be powered by USB type-C or 18650 li-ion bat