EnOcean GmbH PTM215B Manual Do Utilizador
USER MANUAL
PTM 215B – 2.4 GHZ Pusbutton Transmitter Module
© 2016 EnOcean | www.enocean.com
F-710-017, V1.0
PTM 215B User Manual | v0.8 | September 2016 | Page 19/42
The receiving device maintains a list of IRK for all transmitters that have been commis-
sioned to work with it.
Whenever the receiving device receives a radio telegram with private resolvable source
address (identified by the most significant bits being set to 0b10), it will itself generate a 24
bit hash from the 24 bit prand sequentially using the IRK of each device that it has been
learned into it.
If an IRK matches (i.e. when prand is encoded with this specific IRK then the result match-
es hash), then the receiver has established the identity of the transmitter.
So conceptually the IRK takes the role of source ID while prand and hash provide a mecha-
nism to select the correct IRK among a set of IRK.
This mechanism is illustrated in Figure 12 below.
Figure 12 – Resolving private source addresses
2.9.5
Check Sum
The 3 byte BLE Check Sum is used to verify data integrity of received BLE radio telegrams.
It is calculated as CRC (cyclic redundancy check) of the BLE Header, Source Address and
Payload fields.