Guest calling system used in Pet Salon

1)A guest takes his pet  to the pet salon. The salon stuff gives the guest a pager that 

has a ID number.The guest can wait around the salon.for example, to have a cup of coffee,etc.

2)When the pet is ready, the salon stuff  will press the pager’s number on the transmitter.

The corresponding  pager vibrating or LED flashing or sounding, then guest knows he

can take his pet home now.