
Long-Range Wireless Industrial Telemetry
Proprietary FHSS Wireless Ethernet Bridges
SEM Wireless Spread Spectrum Ethernet Bridges
SEM: Spread Spectrum Wireless Ethernet Bridge
(900 MHz – 2.4 GHz)
RFM SEM-series wireless Ethernet bridges provide high-
speed wireless connectivity between distant Ethernet nodes
where cable runs are impractical. All SEMs feature the
company’s patented FHSS technology. Typical SEM uses
include Ethernet bridging, SCADA networking, PLC networking,
and other industrial automation or data collection applications.
SEMs can function as a high speed bridge between two
10/100BaseT Ethernet networks; they can also provide
wireless connectivity between an Ethernet base station and
multiple Ethernet remote modems. Highly complex networks
and extended coverage can be achieved by combining point-to-
point or point-to-multipoint configurations with RFM repeaters.
Product No.
SEM910
SEM910D DIN-rail Mount
SEM910X Remote Radio
SEM910DX
SEM2410
SEM2410D DIN-rail Mount
SEM2410DX
SEM2410X Remote Radio
SEM2411
SEM2411D DIN-rail Mount
SEM2411DX
SEM2411X Remote Radio
SEM2411LC Remote Bridge
Frequency
900 MHz
900 MHz
900 MHz
900 MHz
2.4 GHz
2.4 GHz
2.4 GHz
2.4 GHz
2.4 GHz
2.4 GHz
2.4 GHz
2.4 GHz
2.4 GHz
Transmit Power
1 Watt
1 Watt
1 Watt
1 Watt
100 mW
100 mW
100 mW
100 mW
100 mW
100 mW
101 mW
100 mW
100 mW
Channels
54
54
54
54
75
75
75
75
43
43
43
43
43
Data Rate
172.8 Kbps
172.8 Kbps
172.8 Kbps
172.8 Kbps
460.8 Kbps
460.8 Kbps
460.8 Kbps
460.8 Kbps
1.23 Mbps
1.23 Mbps
1.23 Mbps
1.23 Mbps
1.23 Mbps
The RFM SEM Ethernet Bridges are Class I, Div. 2 certified
in both the 900 MHz and 2.4 GHz bands. SEM bridges include
a standard 10/100 Base-T Ethernet port, antenna, and power
connectors. Five LEDs indicate power status and data activity.
Class I Div 1 versions are available by special order.
The SEM “D” model Ethernet radio is a DIN rail mount version, and the SEM “X” models use a remote, weatherproof, wireless Ethernet radio housed
in a NEMA 4X / IP 66 enclosure.
900 MHz SEM Ethernet Bridges
RFM SEM wireless 900 MHz Ethernet bridge is a high speed/long range wireless networking product that provides 172.8 kbps over-the-air data rate
and over 20 miles demonstrated communications range with 3 dB omni-directional antenna. Uses for a SEM wireless 900 MHz Ethernet bridge include
SCADA networks, PLC networking, and other industrial automation or data collection applications.
2.4 GHz SEM Ethernet Bridges
The SEM2410 and SEM2411 link Ethernet nodes in an industrial communication hierarchy up to 5 miles apart (with gain antennas). The over-the-air
data rate for the SEM2410 is 460 Kbps and 1.23 Mbps for the SEM2411. RFM patented FHSS assures reliable performance even in high-multipath and
noisy RF environments.
Ethernet Radio Security
RFM SEM wireless Ethernet bridges provide multiple levels of security. First, their communications use RFM proprietary frequency hopping spread
spectrum (FHSS) protocol, which is understood only by other SEM Ethernet radio devices configured to use the same hopping pattern (out of 64
possibilities). To ensure that the SEM master communicates only with its intended SEM slaves, the SEM master can be configured to define the precise
number of slaves (up to 62) that can register on the network, and can also be configured to authenticate an ID and password from each SEM slave prior
to granting registration. Finally, SEM Ethernet radios include password protection for both console port and Telnet sessions, and can be configured to
allow the opening of Telnet sessions only from specified IP addresses.
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