If you intend to use your GS-1100-PRO or GS-1100A with Geigerbot on an iPad or iPhone, then you will need this special adaptor cable. The standard mono audio cable that comes with the GS will not work. 

This cable adaptor converts the standard mono jack plug to a TTRS headset connector, and has an integral resistor to mimic the load of an external microphone. It is this resistor which tells the IOS device to switch from internal to external microphone.

If you are handy with a soldering iron, and want to save $25, then you can find instructions on our forum here;

http://www.gammaspectacular.com/phpBB3/viewtopic.php?f=15&t=255&p=1184

Cable length: .......... 50 cm

Resistance: ............. 1 KOhm