Why does the drawer open on a Gigatek DT105 when I don't expect it?

When setting up without a receipt printer (for example, in a situation where everything is printed on a luxury purchase receipt), a USB/Serial device is sometimes used to still open a cash drawer. One option for this is the Gigatek DT105.

However, the Gigatek DT105 is not fully compatible with an Epson receipt printer. The DT105 responds to many more control codes to open a cash drawer, including a change in DTR/RTS.

An important code that the DT105 can respond to is char 7, also known as <BEL>. When this character appears in the print data, the cash drawer will be opened.

For example, when printing a parking receipt, a barcode will be printed consisting of $PT followed by the parking number. An example of a parking code is $PT2023. The total length of this string is 7 characters, and this is indicated before the barcode. The print character for '7' is <BEL>, and as a result, the cash drawer will open.

A possible workaround is to not print a barcode on a receipt. In future versions of RetailVista POS, this can be disabled (after 17.3 and higher). This can be done by adding the text 'receiptbarcode=0' in the advanced settings of RetailVista POS. Unfortunately, in older versions, there is no workaround for these situations.

The DT105 documentation is included in the binaries.