I'm using a different brand, but similar modules. Here is what I learned. With no signal, the RX Data pin pulses randomly. It is a pretty good random bit stream. I did an Audio FFT on it, and is essentially uniformly distributed from 1Hz to 5KHz (the upper limit of my FFT). When a carrier appears, the Data Pin goes high and stays high as long as the carrier is present. If the carrier is interrupted (OOK), the data pin goes low. If the carrier is left off for more than ~1/2sec, the data pin begins pulsing randomly as described above. The transmitter OOKing rate should be somewhere between 10Hz and 4KHz; I used ~1KHz for my project. If you use a square wave to key the transmitter on/off at 1KHz, the recovered data signal is a 1KHz more or less square wave, where there is a lot of jitter on the edges with a weak RF signal, with the edges getting cleaner as the RF signal strength at the RX improves. I used a "tone-decoder" type of circuit to validate that it is my own transmitter I'm receiving...
Since the RX is a super-regen, it is quite broad (+-0/5MHz), so it will lock onto the strongest signal in the neighborhood, even if it is not your own transmitter. Sort of like the capture effect on an FM receiver. When hooked to an outside antenna at my house, I see a lot of ~300ms data bursts, probably from remote reading thermometers, door alarms, etc.
Remember that this is a shared band, and you are not allowed to transmit continuously...