SU-668 has five circuit board chip protection functions: overshoot protection, overdischarge protection, temperature protection, short circuit protection and voltage protection. Fully manage battery, intelligently allocate fast charging and continuous charging, and extend battery endurance and battery life while cycling charging and discharging. The intelligent control chip is used to control input voltage, and accuracy of input voltage is always maintained to plus or minus 1/1000. Avoid battery life shortening caused by voltage fluctuation. Automatically detect battery voltage, when battery is fully , automatically cut off input voltage to avoid danger caused by overcharge of battery. The receiving distance of partition wall is 50-100m. Open receiving distance is 1500 meters. Tips: The distance is too far to reach additive signal intensifier. Thanks for choosing queuing wireless calling system. It adopts wireless technology with millions of different learning codes. The system includes 999-channel call keyboard and portable buzzer& vibration receivers. Each receiveris rechargeable and And it has a number. In standby status, Superposition of charging. while client places an order, he(she) be dispatched one receiver with a number, when order is ready, the keypad to call number, the client through buzzer/vibration/LED indications. The queuing system greatly improve work ef ciency and avoid client waiting in a long queue. It is widely used in fast food restaurant, dessert shop, Coffee house, Pizza shops, auto 4S shop or other queue occasions. Why you use? Minimize crowds in waiting Reduce staff chaos & improve amdience Notify people faster Improve work efficiency Enhances restaurant's inage 999 channels keypad call buttons Superposition charging Portable rechargeable vibration & buzzer receiver storage memory avoiding data lost High receive sensitivity Self testing while power on Beautiful and fashionable design