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Async RS232 to RS422/485 interface converter DB9 to Terminal Block

Convert async RS232 to RS422/485 at speeds up to 115.2 kbps with distances up to 4000 ft over CATx cables in industrial environments with DIN Rail mounting.


Limited Quantity In Stock
Same Day Shipping (before 5PM ET)
Extended Double Diamond™ Warranty Available (3 Additional Year)

*Required field

Product Features

  • A heavy-duty, industrial-strength converter.
  • Converts RS-232 to RS-422/485, extending signals up to 4000 feet (121.9 m).
  • Rugged, IP30-rated metal case for panel mounting.


  • Tolerates temperatures ranging from -30 to +185º F (-34 to +85º C).
  • 2G shock and 3G vibration protection.
  • Boasts 2-kV triple isolation for safeguarding data and equipment.
  • DB9 port on the RS-232 side and a removable terminal block for RS-422/485 links.
  • Data rates up to 115.2 kbps.
  • Modbus® and ASCII/RTU compatible.
  • DIN rail mountable with optional adapter.

    This heavy-duty Industrial Opto-Isolated RS-232 to RS-422/485 Converter makes it easy to convert unbalanced, full- or half-duplex RS-232 to balanced RS-422/485 while extending signals up to 4000 feet (121.9 m).

    Encased in an IP30-rated enclosure, the converter's been put through some of the most exacting tests in the industry. The high-grade converter meets the requirements of two standards that make it suitable for electrical substation installations—IEC 61850-3 and IEEE 1613—specifications that are more stringent than NEMA TS1/TS2 requirements for transportation applications.

    Three levels of isolation.
    The Industrial Opto-Isolated RS-232 to RS-422/485 Converter features 2-kV triple isolation, protecting equipment as well as data from rogue currents and ground loops. It provides powerful isolation on both data ports, and with additional isolation on the converter's power supply circuits, you're given a third degree of protection for your expensive components.

    This level of protection helps prevent stray currents from disrupting important data communications, such as those in factory, engineering, military, defense industry, or utility applications.

    By isolating voltage anomalies, you stand a much better chance of preventing a surge from shutting down an assembly line—or your entire plant.

    Use in point-to-point or multipoint applications.
    You'll need two units for a standard point-to-point application. But you can also easily set up a multidrop configuration, depending on the mode. The box converts RS-232 format data signals to RS-422 for increased range or to RS-485 for increased range and multidrop capability.

    For DCE connections on the RS-232 side, the converter has a standard DB9 port. For RS-422/RS-485 side links, it has a removal terminal block. The Industrial Opto-Isolated RS-232 to RS-422/485 Converter supports serial Modbus® connections for both ASCII or RTU (remote terminal unit) formats.

    Simple to configure and set up.
    RS-422/RS-485 4-wire and RS-485 2-wire DIP switches on the Industrial Opto-Isolated RS-232 to RS-422/485 Converter enable you to configure it for point-to-point or multi-drop operation.

    For additional ease of setup, bit-wise-enabled circuitry detects the data rate automatically—you don't have to set a DIP switch. An automatic send data control feature enables an RS-485 serial port to be used in Windows® applications where you have no control over the handshake lines.

    In addition, the converter has built-in switchable bias resistors (1.2 kilohm) on transmit and receive ports, as well as switchable termination (120 ohm).

    NOTE: At minimum, must be used in pairs. Power supply not included.

  • Tech Specs

    Approvals IEC 61850-3, IEEE 1613
    CE Approval Yes
    Connectors RS-232: (1) DB9 F; RS-422/RS-485: (1) 5-postion terminal block (removable)
    Data Rate 1.2 -115.2 kbps
    Distance (Maximum) 4000 ft. (121.9 m)
    Enclosure IP30-rated metal, panelmount
    Indicators LEDs: (1) Power, (1) TD (transmit data) and (1) RD (receive data) on both the RS-232 and RS-422/RS-485 connectors
    Operating Environment Temperature: -30 to +185° F (-34 to +85° C); Humidity: 0 to 95%, noncondensing
    Power From an external power supply (not included*); Input: 10-48 VDC (56 VDC maximum) on 2-position terminal block (removable); Consumption: 0.5 W typical (1.9 W with termination)
    RoHS Yes
    Size 1.3"H x 3.7"W x 5.2"D (3.3 x 9.4 x 13.2 cm)
    Weight 0.5 lb. (0.2 kg) * See our PS1003 power supply, available separately.
    This product works with:
    At minimum, must be used in pairs. Power supply not included.

    * Technical specification weight is the unit weight. It is not the packaged shipping weight. For shipping weight, please contact Black Box customer service at 877-877-2269.



    Double Diamond Warranty

    Extended 1 Year Warranty Available

    Protect your purchase with an additional 1 Year Double Diamond™ warranty!
    Cost: $25.90

    Extended 3 Year Warranty Available

    Protect your purchase with an additional 3 Year Double Diamond™ warranty!
    Cost: $51.79


    Double Diamond™ Warranty (Standard)

    Take the risk out of equipment purchases with the Double Diamond™ Warranty from Black Box Network Services.

    The Double Diamond Warranty is our warranty that protects your Black Box® brand products* from accidental damage, including drops, water, and power surges.

    The Async RS232 to RS422/485 interface converter DB9 to Terminal Block comes with a standard 5 Year Double Diamond™ Warranty (Standard) already included.

    During the warranty period, Black Box Network Services will repair or replace your damaged equipment within one week of receipt at NO CHARGE!*

    Plus, get an Extended Double Diamond Warranty.

    You can also extend your warranty or protect a previously purchased Black Box® brand product** for an additional year—for only 10% of the purchase price! Or, extend your coverage for a full three years for only 20% of the purchase price!

    Ordering an extended warranty is easy: When viewing a product in your shopping cart, just select the one or three years of additional coverage in the dropdown menu under “Warranty Options.” For details, contact Customer Service at 724-746-5500.

    * Warranty subject to certain exclusions and limitations ** Certain products may not be eligible.

    What’s more, we also have a 45-day return policy. Simply call Customer Service for a Return Authorization (RA) number, return your product in new condition and in the original package, and receive a full refund.