USB - USB Null Modem Cable USB type A plugs on Both Sides Flexible 8ft. Long Serial Communication Null Cable. In the era of legacy PCs with onboard RS232 COM Ports, it was common practice to establish a simple communications network between PCs using a cable popularly known as a Null-Modem cable. Typically, such a cable would have DB9 female connectors on each end with the TX / RX and handshaking signals cross-connected so that the PCs could communicate with each other via legacy COM ports. On modern PCs the legacy COM Port connector is rapidly disappearing as USB becomes the multi-function communication port of choice. However, this presents a dilemma in application areas that previously relied on legacy COM Ports for inter-PC communication. A convenient solution to the problem is this USB USBG-NULL-08 cable. From the outside, this cable appears to be two USB type A sockets wired together, however each of the USB sockets conceal a small PCB with a FT232RQ based USB-UART converter IC plus support components inside. The interconnect cable cross-connects the TXD / RXD data signals, RTS / CTS handshaking signals and interconnects the common GND reference rail betwen the two converter PCBs. When used together with supplied Virtual COM Port ( VCP ) drivers, the USB Null Modem cable may be used to establish inter-PC COM Port based communication at baud rates of up to 3M baud. The standard USB NMC cable p/n USB USBG-NULL-08 comes with an interconnect length of 2.5m ( 8.2ft ) - other lengths may be available on request. Multiple operating systems are supported including Windows, Linux, Mac OS etc.