LFR series RS232/485 Serial Optic Fiber Redundant Ring Converter - LFRMRS24

Lightem LFR series is a RS232/485 Optic Fiber Redundant Ring Converter which can build a
double ring self healing fiber network that greatly improves the stability of the communication of
RS-485/232 serial devices. It also provides either 2 channel RS-485 port or 1 channel RS-232
plus 1 RS-485 port. A two-way half duplex communication is allowed for the 2 channel RS-485

When a segment of fiber is broken or a node fails, the device automatically switches the optical
fiber channel, making the network still working, the communication link is unblocked, and the
safety and reliability of the optical fiber communication network is greatly improved.

LFRMRS24 provides 2 channel RS-485 port or 1 channel RS-232 plus 1 RS-485 port. A two-way
half duplex communication is allowed for the 2 channel RS-485 device. Each LFRMRS24 can work in the master station mode or from the slave mode by the dialing switch, but there is only one master station in the fiber ring and the other as the slave station. When LFRMRS24 is set to
Slave, the RS-232/485 port will only access slave devices.


  • Point to point, point to multipoint, ring network communication mode
  • Two optical ports connect into self healing ring optical fiber network,
    each optical fiber interface can be single fiber or double fiber, and SC/ST/FC can choose
  • 2 channel RS-485 or 1 channel RS-232 plus 1 channel RS-485
  • RS-232 rate 300 to 115200bps, RS-485 rate 0~250K
  • Master-slave mode, one master station mode in the ring network, and other work in slave mode
  • When the slave mode is configured, it can be used as a RS-485/232 serial fiber repeater
  • A maximum of 50 slave stations can be accommodated in a ring network
  • Industrial design, DC9~36V power supply, DIN guide rail installation

Parameters Values
Serial port
2 channel RS-485 or 1 channel RS-485 and 1 channel RS-232
Optical Port
P1: Connect to the next device P2 / P2: Connect to the previous device P1
Communication rate
RS232 rate 300 ~ 115200bps, RS485 rate 0~250K
Connection mode
7 terminal connection
Fiber optic port
2 channel optical fiber port, single / multi-mode SC/ST/FC interface optional, default (SC double fiber)
1310nm (double fiber), 1310/1550 (Dan Xian)
Transmission distance
Multimode 2km, Singlemode 20km
Power supply
DC9~36V/400mA, less than 3W ( VS+: Power positive, VS-: Power negative)
Power connection mode
3 Terminal Connection
Channel 1: R,T,G as (RXD,TXD,GND)
Channel 1: TR+,TR-, Channel 2: TR+,TR
LED indicator
Power indicator, Fiber port 1 and 2 communication instructions
P1: P1 Optical Port Communication Instructions
P2: P2 Optical Port Communication Instructions
Working temperature
-20 C~ +70
Storage temperature
-40 C~85 C
Relative humidity
5% to 95% non condensation
40 (W) mm X 120 ( H ) mm X 90 ( L ) mm

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