How cash drawers work
There are a number of options when choosing a cash drawer to use with a computerised point of sale system.
The most common method is to connect the cash drawer via a receipt printer. Most receipt printers have a port with an RJ11 telephone socket-type connector which can be used to power a cash drawer. These usually operate on a 24 volt signal so a 24v cash drawer is needed.
Your software must be able to instruct the printer to pop open the drawer solenoid at the appropriate time, usually when cashing a sale.
Cash drawers may also connect directly to the point of sale terminal or touchscreen, again usually through an RJ11 drawer connection on the terminal. This can be useful where a receipt printer is not required. This connector usually supplies 12volt signal so a 12v drawer is required.
Though less common, some cash drawers have a usb connector for direct connection to a computer. These smart drawers are more expensive.
Some, but not all printers can operate two cash drawers by using a Y splitter to connect both drawers. Again your software must be able to distinguish between drawers.
Cash drawers are usually shipped with two security keys which can be used to open the drawer, useful in the event of a power cut or if your system is down. Some cheaper drawers are available without an opening mechanism but where the drawer can be locked only using the key.