How to work of wireless calling system

When the guest need any service, they can press the button on the table, the table number will be showed on the RECEIVER of watch or display screen with clear “dingdong” sound or vibration. So the waiter could offer service very timely.

Specification of table call button

3 key: Call; Bill; Cancel                                                  
Signal Distance: 200M in open area     
Material: PC and waterproof silicone
Dimension: 60*60*22mm 
100% waterproof 
With a 12V 23A battery            

Specification of waiter watch

1. Can work with 500pcs multi-key transmitter in max
2. Can show 3 group call number in one time 
3. Show 4-digit number from 0001-9999 and first alphabet can be A-Z
4. Can indicate different service type via words or alphabet. 
    ( call; bill; drink; dessert; help etc and A-Z)
5. Can record when the calling come in and count the call times of each number 
6. Can track the history of calling info by up and down
7. Show current time when stand-by
8. 3 reminder ways: sound prompt and vibration or both 
9. Battery is rechargeable: 3.7V Lithuim battery
10. Dimension: 70*42*16mm
11. Color: Red and Black
12. Output: DC5V--1A