I'm running a pair of UHF CDM1550's in full duplex with one of the new Repeater Builder Rim "lite" RM interfaces: 

It does not look like I can tap the GPIO's very easily on these boards, nor can I tell if GPIO 5-8 is available for general use looking at the schematic: 

What I'd like to do is drive a relay board to switch a fan on if the receiver is active or there is traffic coming in to the node, being connected to another station or hub for example. I read over the GPIO and event management subsystem documentation, and it looks like that's what I need, but I don't have a parallel port nor can I tap the GPIO's on my interface easily (or even know if they can be used as per the above). 

Looking for ideas here if anyone else has encountered this, would prefer the logic/relay board approach vs. say a temperature controlled switch on the heatsink or something. 

73

Stephen

K1LNX