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PTM 210 / PTM 215 / PTM 215U / PTM 215J User Manual May 2020 | Page 16/37
USER MANUAL
PTM 210 / PTM 215 / PTM 215U / PTM 215J
DC Step code and later
3.2.2
Explicit RLC – recommended
This is the recommended secure mode for all frequencies and new applications.
In this mode the PTM does send the RLC inside every data telegram. With transmission of
the RLC in every data telegram a desynchronization of RLC counters between receivers and
transmitter like described above cannot happen.
The receivers use the RLC value inside the radio telegram to resynchronize. The receiver
has to check if the received RLC is higher than the last known value, but he does not have
to apply any window mechanism.
3.2.3
Security Teach-in
A security teach-in telegram is sent by PTM 21x when:
Executing the special button combination for secure mode 2x nibble SBC or 3x nib-
ble SBC – see chapter 3.3 for details.
Triggering the telegram by NFC interface.
The Type of the Teach-in_info in the secure teach-in telegram (
Teach_In_Info : Type
) is:
1-PTM
. The Security teach-in includes required information for the receiver to decrypt fu-
ture data communication.
For more information on the structure of the teach-in telegram please refer to chapter 4.2
of
http://www.enocean.com/en/security-specification/
If the teach-in process is not successful, please repeat the procedure. Due to the
enhanced telegram length of teach-in telegrams in secure mode only a single
teach-in sub-telegram is sent at every actuation (no redundancy).
3.3
Switching between modes
PTM 21x can be switched between normal mode and secure modes by a special button
combination - SBC. There are three types of SBC:
2 nibbles SBC – pressing both nibbles of a channel i.e. AI & AO or BI & BO. This SBC
is used to enter the secure mode with implicit RLC – legacy, not recommended. Pic-
ture below shows both variants
2 nibbles SBC - channel A left, channel B right
