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User Manual May 2019 | Page 41/49
USER MANUAL
Scavenger Transmitter Module
STM 330 / STM 331 STM 331U / STM 332U / STM 333U
(Stepcode DE and later)
5.2
FCC (United States) certification
5.2.1
331U / 332U / 333U LIMITED MODULAR APPROVAL
This is an RF module approved for Limited Modular use operating as an intentional trans-
mitting device with respect to 47 CFR 15.231(a-c) and is limited to OEM installation. The
module is optimized to operate using small amounts of harvested energy, such as can be
collected by a small solar cell exposed to ambient light.
The module transmits short radio packets comprised of control signals, (in some cases the
control signal may be accompanied with data) such as those used with alarm systems, door
openers, remote switches, and the like.
The module does not support continuous streaming of voice, video, or any other forms of
streaming data; it sends only short packets containing control signals and possibly data and
is typically powered by a solar cell in ambient light. The module is designed to comply with,
has been tested according to 15.231(a-c), and has been found to comply with each re-
quirement.
Thus, a finished device containing the STM 331U / 332U / 333U radio module can be oper-
ated in the United States without additional Part 15 FCC approval (approval(s) for uninten-
tional radiators may be required for the OEM’s finished product), under EnOcean’s FCC ID
number. This greatly simplifies and shortens the design cycle and development costs for
OEM integrators.
The module can be triggered manually or automatically, which cases are described below.
Manual Activation
The radio module can be configured to transmit a short packetized control signal if
triggered manually. The module can be triggered, by pressing a switch, for example.
The packet contains one (or more) control signals that is(are) intended to control
something at the receiving end. The packet may also contain data. Depending on
how much energy is available from the energy source, subsequent manual triggers
can initiate the transmission of additional control signals. This may be necessary if
prior packet(s) was (were) lost to fading or interference. Subsequent triggers can al-
so be initiated as a precaution if any doubt exists that the first packet didn’t arrive at
the receiver. Each packet that is transmitted, regardless of whether it was the first
one or a subsequent one, will only be transmitted if enough energy is available from
the energy source.
Automatic Activation
The radio module also can be configured to transmit a short packetized control sig-
nal if triggered automatically, by a relevant change of its inputs, for example. Again,
the packet contains a control signal that is intended to control something at the re-
ceiving end and may also contain data. As above, it is possible for the packet to get
lost and never reach the receiver. However, if enough energy is available from the
energy source, and the module has been configured to do so, then another packet or
packets containing the control signal may be transmitted at a later, unpredictable
time.
