I have a ReplayTV 5504. I'm using the serial port connected to my DirecTV RCA 420 receiver. When I change the channels there is a slight pause for a sec or 2. Is there anyting I can do to speed that up? Since I'm using the serial port I'd think it'd be pretty seemless (not like an IR blaster). Is there any tips you guys have for me to speed it up? Much appreciated.