OK, I have received the RF transmitter and receiver kit, and connected to USB UART as previously described. I have succeeded capturing the data from door/window sensor, all they do is transmit 5 byte data many times when triggered. Maybe they transmit more data, but this is the part that is repeated, and it is enough for the PC part to look for. I can monitor COM Port in PC and when this byte sequence is received I can know which sensor is triggered. The problem remains in simulating the remote control of the Alarm. I can capture the data like the receiver(the repeating 5 or 6 bytes). However when replaying through the transmitter, nothing happens. I don't know if the whole data is only the repeating part or more, also I don't know if my COM port settings are correct.
Here is how my hardware is connected, USB UART is connected to PC. It has 4 pins: RX,TX,VCC (5V), GND. RF Link receiver has 3 pins, VCC(->UART VCC), GND(->UART GND), DATA(UART->RX). RF Link Transmitter has 3 pins, VCC(->UART VCC),GND(->UART GND), DATA(UART->TX)
Datasheet of transmitter suggests 12v, so I also tried putting 12V between VCC and GND pins with a power adapter. (also shorted GND with UART GND to have common ground level) again, nothing happens.
One more thing amazes me is that, if I keep only receiver connected to UART, and trigger sensors, I receive different byte sequences than if also transmitter is connected. And if I supply 12V to transmitter with adapter and only share ground with UART and receiver, the received byte sequences are different again. But since I connect first, learn what to look for byte sequences, then put these values into PC code, understanding when a sensor is triggered is easy, just different for different setups, nothing standard. Also, when receiving, I use 1200 Baud Rate, no parity, 8 data bits, but if I use 1200 Baud Rate, odd parity, 7 data bits, byte sequence is completely different. So this is the problem, I don't know the port settings, I don't know what to transmit.
I suspect that since I don't know actual baud rate, stop bits, data bits etc, I can get away with the receiver part, since I already learnt what to look for before. But I don't know what connection settings and byte sequence looks in the receiver of the home alarm. Is there any way I can know the correct settings and find the correct bytes to transmit?
Initially I thought that since this is serial communication (only 1 and 0) even if I use different COM settings I would still be transmitting same 1s and 0s, only interpreted differently in the receiver part. I guess I'm wrong in that? Can you please help me how to capture the remote control correctly and transmit through my RF link?