Orion electronics offers fully isolated limited distance industrial modem. Dataforth ldm 70 is designed to enable video display terminals [vdts] and other rs-232 devices to be connected over distances to cover any industrial or institutional complex of buildings. This is encased in a small aluminium enclosure saving desk space. The ldm 30 is manufactured for full duplex, asynchronous operation over two, dc-continuity, non-loaded twisted pairs. It has baud rate ranging from 1.2 kb to 57.6 kb and can communicate over a length of 20 km to 0.8 km respectively. Self powered-12 v ac and host powered [draws power from pin 9 and 10] models are available. Each device incorporates a convenient dce to dte switch to reverse pin 2 and 3 of rs-232 connector. Handshake operation is implemented over same two wire pair. Each unit has diagnostic leds on transmit and receive line for installation and troubleshooting. These come in both 9 pin and 25 pin d-type connector versions. Field connection is completed using screw terminations or 4 wire modular phone jack. This gives optical isolation between input and output signals, and protects equipments from industrial surges.
