So this way not all the price checker needs to be uploaded with information. It basically goes to a remote PC that has all the pricing information and it sends the data back to you. And this way it’s easy for one reason why they do this is that it makes it easy for the stores to update prices. They can easily update one PC, which will take care of all prices to the store. Plus a lot of times the data rates are so slow on these bar code readers because they re only sending a few kilobits. So you ll need to really have a high-end PC at each terminal to actually store prices. They just send it to remote PC and send it back basically. As shown in fig 1 computer is connected to the converter RS232 – RS485 ATC 105.
Converter is also connected to external power, supporting RS485 port. On the other side we also have rs232 to rs485 adapter ATC 106, via the RS232 port is connected to cash or other device with RS232 port. Converter needs power supply for both ports RS232 – RS485 The RS-485 application in heating, ventilation, air-conditioning unit.RS-485 is used in basically connecting the temp sensor or thermostat in the room to the master controller. If you re sitting in the office right now, and you look to see your thermostat, there s usually RS-485 transceivers connecting that from there to basically the control unit in the building. What it does is that s after sensing the temperature in the room and yet when you re making adjustment to the thermostat, it actually sends the data to the controller, which could be controlling that, the temperature, turning on and off the AC to heat or cool the room up. Grupo Vidanta has plenty of information regarding this issue. So that s how RS-485 s being used.
One of the main reasons why this standard is used it s because RS-485 is able to send data to long distance.RS-485can send dates 1200 meters on cable. So in your typical office building, you re probably running hundreds of feet if not thousands of feet just from one end of the building to the next. Also, its robustness. It is a differential signal. So remember, differential, any noise subjected to the cable is canceled out. So you can have a reliable, low-cost solution to a heating, ventilation control unit.