Using Virtual Serial Ports (VSP) on Microsoft Windows XP, Vista, or Windows 7
The typical HPSDR rig does not have the CAT interface or a separate PTT serial link implemented in hardware so these ports must be virtual. A Virtual Serial Port program is required to allow two application programs to communicate frequency, mode, and PTT data. Two programs were tried, "Com0com" and "Virtual Null Modem". Com0com is a freeware program and can be downloaded via this link: Learn about and install com0com. Virtual Null Modem is a commercial for profit program that can be downloaded via this link: Learn about and install Virtual Null Modem. Experience with both programs indicate that neither is perfect. Some application programs will not communicate via com0com, and Virtual Null Modem requires a special start-up process on a system restart. Com0Com is recommended by FlexRadio and requires no special start-up attention. So try com0com first and use it as much as you can.