Quote Basket  |  Sitemap  |  Imprint
  • Deutsch
  • English


Signal Powered RS-232 Line Drivers

LDM35 image

The LDM35 series of products is designed to allow video display terminals (VDTs) and other RS-232 devices to be connected over distances sufficient to cover any industrial or institutional complex of buildings. These line drivers feature a rugged enclosure small enough to mount on the back panel of VDT units, saving valuable desk and floor space.

The LDM35 series does not require a power supply for operation. The use of low power circuits and a sensitive optical receiver allows the devices to derive all necessary power from the RS-232 data and control signal. They are designed for full-duplex, asynchronous operation over two, DC-continuity, non-loaded, twisted-wire pairs. Two-wire simplex operation may be accomplished over two wires. The line driver circuits — and, consequently, the host device — are protected from electrical transients due to lightning strikes or operation of heavy industrial equipment.

Each device features a convenient Data-Communication Equipment (DCE) to Data-Terminal Equipment (DTE) switch which reverses pins 2 and 3 of the RS-232 connector. For installation and troubleshooting, each unit has diagnostic Light-Emitting Diodes (LEDs) on the transmit and receive lines.

The RS-232 connector may be ordered as a male or female 25-pin connector. Field connection is made through a modern, solderless, screw-termination assembly.

Circuit diagram Dataforth LDM35

Block Diagram LDM35

PDF Downloads:

  • Produkt Overview LDM
  • Product Overview LDM

  • 2 Modules for Type LDM35:

    LDM35-P RS-232 Interface, Connector LDM35 Signal Powered RS-232 Line Driver
    LDM35-S RS-232 Interface, Connector LDM35 Signal Powered RS-232 Line Driver


    • Baud rates up to 19.200 Baud
    • Max. Distance 19.3 km at 300 Baud
    • Asynchronous 4-wire Full-Duplex, 2-wire Simplex
    • Isolation 300 Vrms
    • Optical Isolation
    • Input Protection
    • LED`s for Installation, Startup and error diagnostics
    • RTS, ,CTS, DTR, DTS and RLSD-Controll-Lines
    • TD and RD Channel-lines
    • Choice of different connectors
    • signal powered
    • RS-232 data lines ±5V - ±15V / RS-232 control lines: ±6V - ±15V
    • Operating Temperature Range 0°C … +70°C
    • Dimensions 91.4 x 53.3 x 25.4 mm
    • CE Compliant
    • Special Solutions on request