Ipaq 5450 digitraveler gps

[cruisin-thru]

I have plugged a tomtom wired gps ifor ipaq 3800 series into an ipaq 5450 and it works fine. I plugged a Digitraveler gps for ipaq 3800 series into 5450 and although it works I dont understand why it initialises the digitraveler to power up immediately, on the ipaq it doesnt illuminate the green light on gps until the gps software sends signal to switch on, however the ipaq 5450 switches on light/power right away so is making gps use power even when not being used. Any ideas why would be appreciated.