PC does not have RS-232 port and/or communication software
RS-232 control ports are common in industrial and scientific equipment and are found in some Vivid Engineering products. Until recently, PCs typically included an RS-232 serial port as well as communication software (i.e. Hyperterminal), supporting easy user access.
Current PCs generally do not incorporate RS-232 ports. Hyperterminal, the communication software included in earlier versions of Windows, was dropped after Windows XP.
Fortunately, there are fairly simple workarounds to both problems:
Adding an RS-232 Port:
Adding an RS-232 port to a PC is easily accomplished with a USB to serial RS-232 adapter. These adapters are inexpensive and readily available online (i.e. Amazon). Vivid Engineering offers an adapter (USB-ADAPTER) that we have tested with our products.
Adding Serial Communication Software:
As mentioned, Hyperterminal was dropped from Windows after XP. This useful link describes Hyperterminal alternatives for Windows 7, 8, etc: