This Digital Adapter, see figure 1 above, plugs into the Digital Out on the following Images series of analog Geiger counters:
GCA-03
GCK
It provides an RS-232 computer output for use with Geiger Counter Graphing program. USB operation requires the use of a USB/Serial Adapter equivalent to IOGear GUC232A.
Program Function
Install the Windows Geiger counter program on your computer. The Windows software may be freely downloaded for non-commercial use only* here:
Download Digital Geiger Counter charting software for Windows XP
Download Digital Geiger Counter charting software for Windows 98