New DB9-USB connectors from FTDI enable to use a USB port in devices with UART interface without necessity of a PCB redesign.
By simple using of new DB9 USB connectors instead of original DB9 UART connectors, you can achieve virtually immediately a USB connectivity of your existing devices. If you from any reasons don´t wish to redesign a PCB, then these connectors are ideally suitable for you. Connectors DB9 USB contain a complete USB/UART converter circuit in their bode. So far these connectors were available in the RS232 logic levels version. Novelty from company FTDI are 4 new types supporting also 3.3V and 5V logic levels – DB9-USB-D3 and DB9-USB-D5, with a USB male or female connector.
DB9 USB family now contains 6 types for all 3 the most common logic levels, in a version with Male and Female USB connector. New connectors offer the same utilization comfort like other USB products from FTDI, DB9_USB datasheet and in the AN_149 application note. Free available drivers enable to use DB9 USB connectors as a Virtual COM Port (VCP).
Change UART to USB in an existing device! - [Link]