In the early days of telemetry, the teams relied on storing data on the car, and downloading the data via a hardwire link when the car came back to the pits. Then narrowband, low data rate (<9.6kbps), radio systems were introduced, and these were complimented by wideband high data rate (>500kbps) burst systems that downloaded a complete laps worth of data as the car passed the pits.
All teams now use a wideband radio telemetry system that broadcasts in the microwave band (1.5GHz to 3.5GHz). Most use a Magneti Marelli system (Ferrari/Renault/BAR/Sauber/Jordan/Toyota/Minardi) while McLaren use a McLaren Electronics (ex-TAG) system and Williams/RBR use Pi Electronics. I think a few teams might also use a narrowband system as well.
I think all these systems are real-time or 'near' real-time in that they instantaneously transmit the signal back to the pits (or more precisely an aerial mounted on a mast which extends from the team truck). When the signal can't be sent, it can be stored for a short time period and then the system 'catchs up' with a bigger 'burst' of data when the communications path is restored.
I'd suggest you try joining the F1Scanner site (
http://sports.groups...group/f1scanner)....there's lots of information there about the radio telemetry systems that the teams use.
HTH,
Jim.