USER MANUAL
STM 350 / STM 350U (STEPCODE DE OR HIGER)
TEMPERATURE AND HUMIDITY SENSOR MODULE
© 2019 EnOcean | www.enocean.com
F-710-017, V1.0
STM 350 / STM 350U User Manual | v1.4 | Dec 2019 | Page 9/14
3.3
Radio telegram format and interpretation
STM 350 and STM 350U transmit telegram data according to EEP (EnOcean Equipment Pro-
file) A5-04-03 which encodes a temperature range of Temperature -20 ... 60°C with 10 Bit
and a humidity range of 0 ... 100 % r.h. with 8 Bit.
In addition, STM350 and STM 350U report their internal energy level using a SIGNAL tele-
gram of type 0x06. The energy status of the module is reported in a range from 0 - 100 %.
The reported value is estimated from the supply voltage level of the energy storage. Charging
situation, life time and high or low operating temperature can lead to fluctuations and devi-
ations of the reported energy level.
Mode change to transport mode is reported by a SIGNAL telegram of type 0x0E.
For details see:
https://www.enocean-alliance.org/what-is-enocean/specifications/
3.4
High security communication
STM 350 and STM 350U support high security communication where the telegram payload is
both encrypted and authenticated.
High security communication can be used to address two main issues:
Unauthorized interception (reception and correct interpretation) of transmitted data
In doing so, a third (unauthorized) party is able to understand the content of a re-
ceived content.
Unauthorized transmission of radio telegrams
In doing so, a third (unauthorized) party is able to transmit a radio telegram that is
treated by a receiver as valid request.
Somewhat loosely speaking, the goal of security has to be preventing an unauthorized person
(often referred to as an Attacker) both from learning about the current state of a system and
from actively changing it.
These goals can be achieved via techniques such as telegram encryption, telegram authori-
zation and dynamic security key modification. All three techniques are supported by STM 350
and STM 350U.
