You may have a basic touch screen pos composed of the cash registered, a card reader, a scanner and such. However, it must be noted that there are other things that you can add in order to make the handling of your current pos terminal go smoother. Yes, thee are a lot of add ons and accessories for your pos terminal that are guaranteed to make your day to day usage and operation run one bit smoother and one bit faster.
Take the case of a power back up that can last for say an hour or so. Yes, power surge may not be that common but there are times that it happens and if you have a battery back up, you are sure to have a sale and a profit whether or not there is electricity.
Another attachment that you may want to include in your pos terminal would be a customer display. People would want to know how much it is that you are going to charge them, people would want to see if a discount is indeed implemented and you can do this by putting a display in the front part of your terminal that way paying customer, most especially in establishments like groceries can see what you see on the other end of the terminal.
Mount screens are another thing that you can consider if you want screens to be mounted from the ceiling. This add-on will help you in saving space but at the same time give the information that a regular screen display gives.
For tablet users, an accessories that charges tablets and is compatible with tablet pos is a must that way synching would be made easy as there are times that encoding of the items that a scanners used in the field can not coincide with the information in the main server.
To put data loss out of the picture an external back up drive is a must as it will help keep track of documents, receipts, transactions and such. Inventories will be made easier; cross referencing will be quicker if you have all your date backed up as you can refer to it should the need to refer to it arise.