No-power RS232 to single mode fiber converters Manual

      The FIB-232-S is RS232 to to fiber optic converter,distance and speed of optical fiber transmission aren’t related. Serial-interface fiber transmission resolves the contradiction of copper transmission’s long-distance and high-speed communications because of it’s advantages such as high reliability, security and confidentiality and so on. The use of fiber as communication transmission medium completely solves the problems such as electromagnetic interference, ground loop interference and lightning damage. It has been used more and more in industrial automation, distributed data acquisition, intelligent transportation, electricity, water, banking and many other areas and become the preferred option for communications transmission.

      FIB-232-S is an industrial grade RS232 to fiber converter of Fourstar. It achieves RS232 signal’s transparent transmission on fiber, without changing the original communication protocols and software, plug and play, and directly replace copper Conductor transmission. The product needn’t additional power, and use MAXIM IC technology to from the RS232 serial port’s TXD, RTS and DTR signal line to supply power, regardless of  what states are of these three signals. In fact for some RS232 serial port, only TXD can filch enough electricity to ensure the normal work of product.

Product characteristics and major technical indicators

● transmit signals of RS232 serial port’s  TXD, RXD, GND three wire

● baud rate adaptive, transparent data transmission, without changing the original communication protocols and software

● working voltage: Serial interfaces TXD, RTS and DTR needn’t external power supply. If the power supply of serial interface is inadequate, 5 ~ 12 VDC power can be added

● working current: <20 mA

● serial interface characteristics: EIA-232 standard level, DB9M pin socket with DTE standard interface, with ± 15kV ESD protection and surge protection

● communication rate: 0 ~ 230 Kbps Adaptive

● applicable fiber: single-mode 9/125、10/125、8.3/125um

● wavelength: 1310 nm

● power of launched light: -6 dBm

● receiving sensitivity: -22 dBm

● transmission distance: 0 ~ 20 km

● fiber interface: standard ST connector, SC and FC connector optional

● temperature: -40 ~ +85 ℃

● Relative Humidity: 0 to 95 percent (not condensed)

● Dimensions: 85 × 55 × 25 (L × W × H), the standard rails installation with bolts hole

● Weight: 100 g

The structure and shape of products:


DB9M neilsbed RS232 socket

Pin number





Not be used, to short with 4、6



RS232 signal receive



RS232 signal send



Not be used,to short with 1、6



RS232 signal ground



Not be used,to short with 1、4



Not be used,to short with 8



Not be used,to short with 7



Not be used

Using method

      For the RS232 interfaces with standard DTE way such as computer, you can directly use the RS232 socket with the product witch connect RS232 cable to fiber converters. For RS232 interfaces of non-DTE way (such as some industrial equipment’s RS232 interface), users need a self-made cable to connect the fiber converter and RS232 interfaces of equipment, and the connectivity principles are: connect sending to receiving, receiving to sending, ground to ground. Determine whether short the unused signal as the equipment’s introduction book. RS232 cable’s length can not be over 15 m.

      Use fiber to link the two fiber converters. Connect Tx to the other one's Rx, Rx to the other one’s Tx.  The bend radius when laying the fiber can’t be less than the allowed one, or the core is easily broken.

      After fiber converters and equipment’s RS232 interface are properly connected, the power indicator light PWR on the converters was lit. If PWR was not lit, it means the connection is wrong or the equipment’s RS232 serial port lack of electricity (as possible as you can to connect in RTS and DTR signals to provide more power). Now the power supply need an external power. The voltage of this external power is 5-12 DC.

There is a LED indicator FIB besides the fiber connector Rx. When the fiber is broken, the fiber is not connected or the opposite party’s fiber converters is turn off, FIB will be lit by receiving the matt signal, witch is very convenient to judge where the fault is.

      Please pay attention to maintaining the clean of fiber’s interface socket. Please

      use the configured rubber to cover it when it isn’t connected.