User's Manual

2.5 Serial Data Communication via Receiver Device RCM 120
The RCM 120 Receiver Device of EnOcean enables standard asynchronous communication to
a micro-controller or personal computer with a decompressed and simple data structure (9600
bps, 1 start bit, 8-bit data byte with LSB first, 1 stop bit).
Figure 19: Receiver device RCM 120
When the RCM 120 receiver is set to Mode 0 “Serial Interface”, it transfers out data blocks of
information from the received RF telegrams. For a complete transmitter message, a telegram
of 14 data bytes is transferred via the serial link. The data block format is explained in detail in
the RCM 110/120 User Manual.
Type of STM 250 protocol is “1BS” (One Byte Sensor):
ORG byte = 6 dec. always (EnOcean device type “1BS”)
DATA_BYTE3 as follows:
Bit 7 Bit 3 Bit 0
Reserved LEARN Reserved STATE
Bit 0: STATE
STATE = 1: magnet present (Window CLOSED)
STATE = 0: no magnet (Window OPEN)
Bit 3: LEARN
LEARN = 1: LRN pushbutton not pressed
LEARN = 0: LRN pushbutton pressed
Bits 2..3 and Bits 4..7: reserved
DATA_BYTE2 = 0
DATA_BYTE1 = 0
DATA_BYTE0 = 0
ID_BYTE3 = device identifier (Byte3)
ID_BYTE2 = device identifier (Byte2)
ID_BYTE1 = device identifier (Byte1)
ID_BYTE0 = device identifier (Byte0)
©EnOcean GmbH, A. Anders Page 17 of 24 STM 250 User Manual V1.3