USER MANUAL
STM 429J – Scavenger Transmitter Module
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STM 429J User Manual | v2.0 | Nov 2017 | Page 8/ 17
2
FUNCTIONAL DESCRIPTION
2.1
Block diagram
A change of the reed contact status or pushing the LRN button will wake the transmitter
unit to send a radio telegram immediately (reed contact position, LRN push button status,
unique 32-bit sensor ID (at profile teach-in 48 bit ID), checksum).
In addition a redundant retransmission signal is sent to announce the contact status even
in case of no input signal changes. This signal transmitted every 20-30 min, affected at
random. The transmit indicator LED flashes briefly at every radio transmission.
Between the wake-up phases, the device is in sleep mode for minimum power consump-
tion.
2.2
Radio telegram
429J transmits a radio telegram according to EnOcean Equipment Profile
EEP D5-00-01 as defined in the EnOcean Equipment Profiles specification.
2.3
Secure radio telegram
The STM 429J can be operated in:
Standard mode – no enhanced security is used. This is the common operation mode,
originally available. This is also the default factory mode.
Security mode – communication is protected by enhanced security features. This
mode was added later in module evolution.
2.3.1
Switching between modes
STM 429J can be switched from normal mode to secure mode and vice versa by long press
of the LRN Button (Wake 1).
The behaviour of the LRN button is following:
