If you wish to switch from the RS232 to USB then it will require a number of changes. There are a number of RS232 to USB adapters on the market. You can see below the different drivers for the different hardware that is available on the market. There are only three major hardware suppliers for the RS232 adpater. You can see these listed below. These are the USB driver.
RS232 to USB driver
The most commonly used chip is made by Prolific and the PL2303TA is a USB driver has been added to this website. You can see that this is cross connecting a PL2303TA to a RS232 driver adpater. These are cross adapter and you can find those here. The following are others such as the RS232 to USV driver which is explained below.
There is a Linux driver as well. The RS232 to USB for Linux is found here. There is also a Windows version for the Prolific RS232 to USB for Windows which is listed here. These are for the Prolific hardware chip you will find in the majority of the adapters. There are also other drivers. These can be Prolific as well as FTDI UART drivers. You can find the RS232 to USB FDTI drivers here.
These are the drivers which you will find on this website. There are mainly the two drivers being the Prolific and the FDTI which you will find here. Also note that the FT232R driver which is also common with adapters in this range. There is also the USB to RS232 driver which you will also find listed with the driver here.
The FTDI as well as Prolific are the most common drivers and hardware you will find on the market. You can also see how to install these and also see other hardware on the market place. Search this website for more information in this regard. See also the Prolific USB to Serial Driver on this website.