Belkin Tunecast Ii

I am using the above to tx audio from my PDA satnav to my car stereo. The unit powers down if no input is present after a 30 second delay. This is OK if using batteries. I want to disable this power down feature.

Does anyone have any ideas? There is a 47micF cap, is this the RC timing cap?

Does anyone have a circuit for this devicew? The main chip is BW007E.

Thanks.

How about introducing enough noise to the signal line to think a signal is constantly present? A tick every 29 seconds, or maybe just raising the noise floor. If this is overlayed on another signal especially in a car the noise floor is going to be well bellow ambient.