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IRSFC24 : 3KV Opto/Xformer Isolated RS232 to RS485 2 Wire Half Duplex Converter



IRSFC24 Label

"Let me spin a very large
RS485 network for you!"


Product Features:

  • This 3KV Isolated auto transmit unit features Bi-directional serial conversion from RS232 to RS485 in 2 wire half-duplex communications mode.

  • Optimized for Isolated office/indoor/outdoor point to point, or multi-drop systems.

  • Transparent to all asynchronous data, with any combination of data, parity, and stop bits, at data rates up to 115.2Kbps. 

  • Fast auto turn-around, from transmit to receive mode, requires no software delays and eliminates timing problems and data collisions. Jumper J8 can further shorten the turn-around time to accommodate fast responding target devices. We pioneered this leading edge technology long before our competition.

  • The RS485 driver is protected by auto-reset fuses, a transient suppressor bridge, and built-in ESD tolerance. It can drive 32 standard loads at 4000 ft. at data rates up to 115.2 Kbps.

  • Jumpers allow the RS485 termination, two levels of bias resistors, and the RS232 DTE/DCE mode to be user configured. Jumper J7 will place the unit in Loop-Back mode for self test.

  • Edge mounted LEDs display isolated power, and RX and TX data activity at both interfaces. 

  • Pull-up resistors are built-in to accomodate RS232 devices that need inputs: CTS, RTS, and DSR. This unit does not require these, or any other control signals, to operate at maximum performance. 

  • A polarity protected switching power regulator accepts supply voltages from 9 to 35VDC, at 0.5 Watts max. 

  • Broad environmental range. Temperature: -40C to +85C(-40F to +185F). Humidity: 10 to 90% RH(non-condensing)

  • Four(4) easy mount through hole standoffs, which accept #6 hardware, are provided on the circuit board.

  • User connectors are an RJ11/12 telephone style for the RS232, 2 RJ11/12 telephone style and a 3 pin Wago style for the RS485, and a 2 pin screw terminal strip and a 2.1 mm barrel connector for the power. 

  • Accessories available are a 12VDC Switching Power Supply(Wall Wart), an enclosure, and a 7ft  RJ11/12 to DB9F RS232 cable.

  • Conformal coating, cables, and connectors, are factory options. Contact us for options help.

  • R E Smith Inc makes a wide variety of isolated converters that address the electrical noise problems that contribute to unreliable communications, and product failure. 

  • We also have a new series of Converters and Repeaters that extend the RS485 communications distance far beyond conventional limits.

  • If what you see here is not exactly what you need, don't hesitate in calling us at 513-874-4796.

  • WARNING: Do NOT connect this device to a telephone system under any circumstances. Damage could result to the circuit board and/or your telephone system.

About R E Smith, Inc.

R E Smith, Inc. engineers and manufactures a comprehensive line of isolated and non-isolated converters, repeaters, multiport repeater hubs, fiber optic based products, and I/O boards. All our products are designed, built, tested, and shipped from our facility in the Greater Cincinnati Ohio area. We ship small quantities of most products from stock the same day, and larger quantities in a few business days.

We listen to you. We are customer driven. Many of our products were developed and improved due to suggestions and feedback from our word-wide customer base. They are being used at the South Pole, at the bottom of the sea, at the edge of space, and everywhere in between. Typical uses are very large networks, monitor and control of elevators, machinery, lighting, security, fire and alarm, access, cameras, military ground support, and much more. We provide free support, no-argument warranty repairs, and recommendations for your application. Challenge us with your communications problem. We may already have the solution. If your system keeps failing, or is unreliable, we have isolated, doubly isolated, noise resistant, cost effective, and proven solutions for difficult environments.

Related Files:

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Data Sheet Rev. C
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Converter schematic/physical Rev. C

Physical Properties and Features:

RS232: 3-wire interface to RJ11/12 Connector (TX, RX, Common)
RS485: 2 RJ11/12 Connectors, and a 3-position Wago style terminal strip
Power: 2.1mm barrel connector and 2 pin screw terminal strip
LEDs Edge mounted isolated power, RS232, and RS485 Data activity
Bias: 910/2.2K Ohm pull-up and pull-down (jumper selectable)
Termination: 120 Ohms (jumper selectable)
Protection: Transient Suppressors inside a diode bridge, auto-reset communications fuses, Sipex SP485REP/EEP Driver with built-in ESD tolerance


Distance: Up to 4000 ft. (1220 meters)
Operation: 2-wire half-duplex RS485
Format: Asynchronous data with any combination of data, parity, and stop bits
Speed: Up to 115.2Kbps
Environmental:   -40 to 85C ambient, 10-90% RH non-condensing
Supply Power: 9-35VDC at 0.5 Watts typical + external loads
Size: 3.50" X 3.00" X 0.9" (PC Board), with connectors: 3.50" X 3.25"
Mounting: 4-Holes 3.00" X 2.25" (built-in standoffs for #6 hardware)

Options and Ordering Information:

IRSFC24: $99.00 ea. (Circuit board only)
Enclosure: $10.00 ea. (Medium)
Cable: $7.50 ea. (RS232, 7 ft., specify DB9F-7 or DB25F-7)
Supply: $8.50 ea. (12VDC/0.5A switching regulated wall power supply). Meets California and most world wide safety and efficiency standards

This the IRSFC24 unit showing the complete order number

IRSFC24 with all options (DB9F cable/Enclosure/PS): Order Number: IRSFC24-B9FSPS @ $125.00 ea. (Qty. 1-9)

Need a different configuration or more information? Give Ron a Call at 513-874-4796 or 513-638-0228(Cell)

Webstore: IRSFC24

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