queue wireless calling system electronics 3 number receiver host keypad caller

keypad : it call number from 001-999.it can call back any number and recall any number.it with a next key,press next+ent ,then number will goes to next number. display : it can be wall intalled or deskstyle.and can dingdong beeper or promot english voice to announce number change.
display voice mode,volume ,promot times,brightness can be adjustable. how to work: give a numeric serial number within 999 to the customers, when order is ready just press the number you want to call, the wireless display will voice accompanied by number display.syi