The LDM30 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 modems feature a
rugged aluminum enclosure small
enough to mount on the back panel of VDT units, saving valuable desk
and floor space.
The LDM30 Series is designed for
full-duplex, asynchronous operation
over two, DC-continuity,
non-loaded, twisted-wire pairs.
Through special high-speed
optically-coupled circuits they may communicate at data rates up to
57,600 baud. A self-powered model
and a host-powered model are
available. The self-powered unit
uses 12 Vac from a wall-mounted
transformer while the host-powered
unit takes ±DC power from pins
9 and 10 of the RS-232 connector.
The modem 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.
Alternatively, a convenient four-wire
modular phone jack is available.
† All dollar amounts on this site are shown in Singapore currency.
Note: Includes operator’s manual. Transformer powered units also include 120 Vac wall mount
transformer.