Digital-I/O Extender Set 2*In / 2*Out Multimode ST


Reliably transmit switching signals over long distances

The Digital-I/O Extender Set 2×2 transmits up to four digital I/O signals over multi-mode glass fiber cable. The Set consists of two Converters Digital-I/O <> glass fiber optics and supports two I/O channels in each direction.

Manufacturer: Wiesemann & Theis / Country of Origin: Germany



  • 2 x digital output
    • FET, short-circuit protected, 8..30V / 0.5A
  • 2 x digital input
    • Polarity reversal protected
  • 1 x multi-mode fiber optic cable
    • ST connector

Management and connectivity:

  • Noise-immune transmission of four I/O signals over a distance of up to 3800 meters e.g.:
    • in extremely noisy industrial environments
    • in areas subject to lightning strikes
    • between two distant buildings
    • in the mountains
    • ….
  • Configurable output response when glass-fiber cable is interrupted

Power supply:

  • External
    • 12V-24V DC via plug-in screw terminal
    • Galvanically isolated power connection

Standards & more

  • Conforms to standards both in office and industrial environments:
    • High noise resistance for industrial environments
    • Low noise emission for residential and business areas
  • 5 year guarantee

Worth knowing

Although digital I/O signals are essentially insensitive to external noise due to their low bandwidth and the large voltage swing, as serial data signals for example the application conditions do still in many cases require transmission procedures which are completely resistant to local noise effects.

Glass fiber optic cables used as the transmission medium meet these requirements in ideal fashion and also offer the advantage of galvanic isolation of up to virtually any value between the connected devices. In installations which are subjected to high risk of lightning strikes, for example in outdoor locations or between distant buildings, such a solution ensures that the connected components will survive even under adverse conditions.

Plastic fibre optics have the advantage of simple to install connections over short distances of up to 100 meters, but at distances up to 3800m the use of glass fiber optics is mandatory. Light signal attenuation is significantly less in glass optical fibers compared with plastic.

Whereas routing and assembling glass fiber optic cables used to be problematic for the user, increasingly wide usage of glass fiber optic technology in networks has caused many companies to offer this service today at reasonable cost.

Technical data

Connections and displays:

  • Transmitted signals:
    • 4 digital signals (two in each direction)
  • I/O connection:
    • Plug-in screw terminal
  • Digital outputs:
    • 2 x Digital Out 6V-30V, 500mA, short-circuit-protected
    • Configurable response to cable break
  • Digital inputs:
    • 2 x Digital In, max. input voltage +/-30V
    • protected against reverse connection within this range,
    • Switching threshold 9V ± 1V, “On” current = 2.2mA
  • Glass fiber connection:
    • ST plug adapter
  • Signal propagation time:
    • Input to output: max. 250μs
  • Fiber-optic medium:
    • Multi-mode fiber 50/125μm, 62.5/125μm
  • Wavelength:
    • 820nm
  • Optical budget:
    • 50/125µm: typically 9.6dB, min. 4.2dB
    • 62.5/125µm: typically 13.4dB, min. 8.0dB
  • Maximum distance:
    • 50/125µm: typically 3200m, min. 1400m @3dB/km
    • 62.5/125µm: typically 3800m, min. 2200m @3.5dB/km
  • Galvanic isolation:
    • Isolation voltage min. 1 kV DC between the I/O terminal and supply voltage
  • Supply voltage:
    • 12V..24V AC/DC
  • Current consumption:
    • typ. 50mA @12V DC
  • Supply connection:
    • Plug-in screw terminal, 5.08mm spacing
    • Labeled “L+” and “M”
  • Displays:
    • 1x LED Data
    • 1x LED Power

Housing and other data:

  • Housing:
    • Plastic housing for top hat rail installation
    • 105 x 22 x 75mm (L x W x H)
  • Enclosure rating:
    • IP20
  • Weight:
    • approx. 200g
  • Ambient temperature:
    • Storage: -40..+70°C, Operation: 0..+60°C
  • Permissible relative humidity:
    • 5..95% RH (non-condensing)
  • MTBF:
    • 339,383h @25°C per MIL-HDBK-217
  • Life expectancy:
    • > 25 years at 25°C ambient temperature
  • Scope of delivery:
    • 2 Converters Digital-I/O <> glass fiber optics
    • If needed please order power supplies as separate accessories
Weight 0.2 kg