+ AA6YQ comments below
The IC-7800 has a DB9 jack marked RS-232C that provides a built-in CI-V interface.
+ You're right, Joe. Later Icom transceivers provide a USB connection with a built-in CI-V interface, but the IC-7800 provides an RS-232 connection with a built-in CI-V interface
73,
Dave, AA6YQ
