datasheetbank_Logo
Integrated circuits, Transistor, Semiconductors Search and Datasheet PDF Download Site

KTX2 View Datasheet(PDF) - Radiometrix Ltd

Part Name
Description
View to exact match
KTX2 Datasheet PDF : 8 Pages
1 2 3 4 5 6 7 8
Notes on the KTX2:
1. The Module will transmit if any of the function lines (S0 – S3) is activated (high).
2. Single message time is typically 150ms.
3. Whilst S0 – S3 are all deactivated (low) standby current consumption is <1uA.
4. The Module will transmit the same message (with the same hop-code) repeatedly whilst any of
the function lines are held active high, until power-saving time-out occurs after approx. 30s.
5. When the power-saving timeout occurs, current consumption will be <350uA, until all function
line(s) are released again.
6. Whilst a function line is held high, if another function line is taken high then the function code
in the message changes to reflect the new state of the function lines and the hop-code is also
changed – as if the user had released all function lines and activated the new combination.
7. Releasing individual function lines (whilst at least one function line remains high) has no
effect on the transmitted message.
8. The supply monitoring status bit is set when module supply drops below 3.8V (approx.) and
resets when supply falls even further – below 2.2V (approx.) – but note that this is less than
the minimum supply recommended for use with KTX2.
Description of the KTX/KRX code hopping system:
Every time a function code is activated causing KTX to transmit, a hop-code is generated. The hop-code is
an encryption based upon a Manufacturer code and the module ESN (unique to each module). An
encryption algorithm uses these two variables to generate the hop-code, which will change for every new
transmission. Note that the data itself (i.e. the function code) is not encrypted, as it is the identity and
status of the sender that is used to safeguard operation of the system.
At the KRX receiver-decoder, the hop-code can only be decrypted with the correct key. The key is derived
from the manufacturer code and the KTX serial number. The manufacturer code is not transmitted: it is
pre-programmed into the decoder. Because the hop-code is changed for every new transmission the
receiver decoder must be synchronised to the transmitter encoder. This is achieved by “learning” the
transmitter to the receiver during which the serial number and synchronisation data is stored in the
receiver-decoder. Transmissions received from all KTX modules are decoded, but not acted upon unless
the serial number has been learned first and the decoder is synchronised to the encoder.
If the Radiometrix KRX decoder loses synchronisation with the transmitter (e.g. repeated transmitter
activation whilst out of range) then the KTX module must be activated twice before the decoder will allow
the control to be processed, but only if the KTX module is within a forward window of +32768 activations.
This mechanism prevents “code-grabbers” from breaking the security of the system by recording and re-
broadcasting old codes. Additionally, in the KRX decoder a window exists allowing up to 14 transmissions
to occur whilst the transmitter is out of range before two valid sequential transmissions are required to
use the system. In practice a user may not notice the latter, since human reaction to an unsuccessful
attempt is simply to “press the button again”.
Radiometrix Ltd, KTX2 Data Sheet
page 3
 

Share Link: 

datasheetbank.com [ Privacy Policy ] [ Request Datasheet ] [ Contact Us ]