The pitot probe has two sources of "ram air" pressure (called Pt1 and Pt2). If you peer inside the probe with a good flashlight you can see them branch. One of these is supplied directly to the Airspeed/Mach Indicator (AMI) to compute how fast the jet is moving through the air molecules. Pt is also sent to devices (The CADC and the PSA)to convert the air pressure into an electronic signal for use by the flight controls. The CADC also passes this information on digitally to the fire control system, where it's used for lots of stuff, including displaying Airspeed and Altitude on the HUD. The pitot tube also has some tiny little holes which provide a signal to the AMI, Altimeter, d flight controls, and the CADC and is called Static Pressure (Ps1). You can think of this as working kind of like a barometer. Ps is critical in the computation of true and calibrated airspeed, altitude, and mach.