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304042 - Model 4042 High Speed ST Fiber to RS422 Interface Converter

    ST Fiber to RS422 Interface ConverterST Fiber to RS422 Interface ConverterST Fiber to RS422 Interface ConverterST Fiber to RS422 Interface Converter
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    • ST Fiber to RS422 Interface Converter
    • ST Fiber to RS422 Interface Converter
    • ST Fiber to RS422 Interface Converter
    • ST Fiber to RS422 Interface Converter
Base Price:
Catalog No: 304042
Model No: 4042
Product Type:Interface Converter
Converter Port Connector:DB9, ST
Conversion Type:Glass Fiber, RS422
Feature:Operating temperature -40°C to 85°C, Conformal Coated Circuit Board
Speed:RS422 0 to 5 Mbps
Wavelength Nano:820nm/850/nm, multimode

NOTE: This unit has conformal coated circuit boards and a wide temperature rating of -40°C to 85°C.




Shipping Terms

Shipments are made via UPS Ground, unless otherwise specified. Freight charges are prepaid and added to your invoice. We can estimate the freight costs for you.

We can ship freight collect on your account, just provide your UPS Account Number.

We can also ship via the carrier of your choice. Provide the details and your account number.

Products shall be shipped F.O.B. Electro Standards' facility. Title to and risk of loss or damage to the products shall pass to you upon Electro Standards delivery of the products to a carrier for shipment. Title to software will remain with the applicable licensor. Electro Standards' prices do not include shipping and handling charges. Electro Standards reserves the right to use its own discretion in the manner and routing of shipments. Electro Standards shall be permitted to deliver products in separate lots.

Shipping Return Policy

  • To return an item, contact Electro Standards at 401-943-1164 to obtain a Return Material Authorization (RMA) number. RMA numbers are valid for 30 days after the date of the shipment and cannot be extended or re-issued. We are unable to accept returns without an RMA number.
  • All returns except those of defective product are subject to a 15% restocking fee, and additional charges for handling or freight are refunded only in cases of defective products.
  • Return freight must be shipped prepaid. We recommend that you insure the package as you are responsible for risk of loss on all returned packages. We recommend that all cartons are properly packed as Electro Standards is not responsible for product damaged en route. We do not issue call tags for product returns.
  • Returned product must be clean, undamaged, and complete with all manuals, accessories, documents and packaging. The items must be in a resalable condition.
  • The product must have with it a copy of the original invoice or packing slip and the appropriate RMA paperwork.
  • If your item is not working properly, please contact Electro Standards at 401-943-1164 for help in trouble-shooting your application.
  • If the product is defective, Electro Standards will repair or replace that item (at our discretion) upon receipt and evaluation of the original product.
  • Electro Standards reserves the right to authorize product returns after 30 days from the invoice date in some cases. If the product is accepted after 30 days, credit will be issued toward future pruchases only and some additional restocking charges may be applied.
  • All credits from RMAs must be used within one calendar year of issue.

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Interface Converters, Glass Fiber to Copper
Very High-Speed Ruggedized ST Fiber-to-RS422 Interface Converter

  • Field proven, highly reliable performance!

  • High quality manufacturing consistency maintained via established Design Documentation Control.

 The Model 4042 is a high- speed ruggedized ST Fiber to RS422 interface converter.  Typical operating speeds are up to 5 Mbps for RS422 to fiber conversion.  When operating in RS422 mode, the converter is configured for 4-wire full duplex operation.

Model 4042 Very High-Speed Ruggedized ST Fiber-to-RS422 Converter Block Diagram

Model 4042 Ruggedized ST Fiber-to-RS422 Interface Converter


  • The converter provides an industrial solution for applications requiring a single point-to-point or a communications link over short and long distances. 
  • PC to PC Long Distance Communications
  • Factory Automation
  • Data Collection Devices
  • Barcode Readers
  • Time Clocks, Scales
  • Data Entry Terminals, ATM's
  • Serial Communications in Harsh Environments

The Model 4042 is designed to operate from -40°C to 85°C.  The unit features ESD protection circuitry on the RS422 copper interface.  The power input is protected from transients, as well as, over voltage and over current.  The converter is powered from a +5V power supply or a +28V power supply via the DB9 connector.  Other features include user selectable fiber polarity, TX, RX and Power indicator LEDs.


  • Model 4042 converts ST Duplex Fiber to Copper RS422 DB9 (F) port.
  • Supports constructing an optically isolated high-speed communication link between connected devices.
  • Typical operating speeds are up to 5 Mbps for RS422 to fiber conversion.
  • Provides full galvanic isolation (no metallic connection) between connected devices.
  • LED Status indicators display Fiber RX, TX activity and power indication.
  • Circuit boards conformal coated in accordance with IPC-CC 830 using the type of UR Class B using HumiSeal A133 Urethane conformal coating.
  • The circuit board is fabricated to Class 2 standards.


 Fiber Interface:

Connectors: Fiber Optic ST Female, Multimode

  • TX Power: -12.5 dBm
  • RX Sensitivity: -27.5 dBm
  • Optical Budget: 15 dB
  • Max. Link Distance with 62.5/125µm fiber:
  • 5.35 kM at up to 5 Mbps, 25°C
  • 3.75 kM at up to 5 Mbps, -40°C to 85°C
  • Wavelength: 850 nm, multimode
  • Fiber Size: 50/125 µm, 62.5/125 µm, 100/140 µm.

Copper Interface:

  • Connectors: DB9, Female
  • Type: RS422 (4-wire)
  • Terminations: RS422 120 Ohm jumper selectable

Bit Rate (nom.):

  • RS422: 0 to 5 Mbps

Network Configurations:

  • RS422   Point-to-Point




  • Input Power: 5VDC or 28VDC.
  • Connectors: DB9F Pin 9 (+5V), Pin 1 (+28VDC), Pin 5 (GND)

Operating Environment:

  • -40°C to 85°C

Model 4042 Mechanical (Desktop Unit):

  • Model 4042, Cat No: 304042
  • Size: 2.36" x 1.77" x 0.95" (60mm x 45mm x 25mm)
  • (Does not include connectors beyond the enclosure)
  • Weight: 0.5 lb (226g)

 MODELS 4165, 4165-DIN, AND 4166 to MODEL 4042 APPLICATION:

PC/Host USB (Copper) to Multimode Fiber Link (Glass Fiber) to DB9 (Copper) to RS422 Serial Interface / Network. (Models 4165/4166 to Model 4042)

Models 4165, 4165-DIN & 4166 to Model 4042 application drawing

MODEL 4042 to MODELS 4152, 4153 APPLICATION:

From a Controller RS422 to Multimode Fiber Link (Glass Fiber) to DB9 (RS485/422/232) (Copper) to a PC/Terminal. (Model 4042 to Models 4152/4153)

Model 4042 to Models 4152/4153 application drawing

MODEL 4042 to MODEL 4179 APPLICATION (RS422 to Multimode Fiber to (POF) Fiber):

From a Controller to ESL Model 4042 RS422 (Copper) to ST Fiber to ESL Model 4179, SC Fiber (Glass Fiber, Multimode Fiber Link) to POF Fiber (Plastic Optical Fiber, Versalink).

 Model 4042 to Model 4179 application drawing, RS422 to Multimode Fiber to  POF Fiber

To view more of Electro Standards' Media Converters, click here: Interface Converters.

Electro Standards can supply all your Network Cable requirements. Click here to reach our CABLES, CONNECTORS/ADAPTERS Webpage.

For custom network interface converters call our friendly customer support staff at 401-943-1164, email eslab@electrostandards.com, or complete our online form: /Products-Custom/Copper-Switch/

All data switches, data communication products, and data acquisition products are subject to a one year warranty against manufacturing defects.  The limit of ESL liability is limited to the cost of the ESL product provided.

*Prices online are subject to change and verification.

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