Off Topic?? - Serial coms.

[skimask]

A quick idea. Have not tried.

Input from Serial charges cap. When voltage is high enough to start pic, P1 goes high switching signal to P2. P2 receives signal. P3 sends signal. Cap would be 4700 or larger.

I'd use a small battery pack rather than a cap, trickle charge the pack off the serial line when you can, diode block it so the pack can't feed back into the data line. Cap's are too unreliable in cases like this.