DN-900 Series Modem Operation
The DN-900 series 900 MHz modems provide high perfor-
mance, ready-to-use solutions for robust wireless data com-
munications in the 900 MHz ISM band. There are currently
three products in the DN-900 series, the DN-900G, the
DN-900I, and the DN-900U. The DN-900G provides an
RS-232C serial interface with optional flow control. The
DN-900I offers a two-wire, multi-drop RS-485 interface plus
a selectable three-wire RS-232C interface for configuration
programming. The DN-900U provides a USB interface.
DN-900 series modems are based on RFM’s DNT900 fre
-
quency hopping spread spectrum (FHSS) transceiver, and
can communicate with other DNT900-based RFM products,
as well as customer developed products.
As shown in Figure 1, DN-900 series modems consist of a
radio module in a NEMA 4X/IP66 waterproof case with an
internal 2 dBi directional antenna, a signal cable that carries
power and data, and an interface adaptor that includes a
power supply connector and the appropriate serial data con
-
nector. The radio module can optionally be provided with a
RTNC antenna connector in lieu of the internal antenna (see
Ordering Guide on Page 5). DN-900 serial modems with the
RTNC connector are compatible with RFM’s complete line of
900 MHz antennas, allowing extended operating range
where allowed by local regulations.
DN-900 series modems are supplied with a 110/220 VAC
wall-plug power supply that includes an international plug
set. Optionally, DN-900 series modems can be powered
from a user-supplied DC source as described in the specifi-
cations table. The signal cable can specified as 4, 50, 100 or
300 feet in length (see Ordering Guide on Page 5), which al-
lows the radio module to be located remotely indoors or out-
doors at a point of good RF propagation. DN-900 modems
can transmit data from 38.4 to 500 kbps, and the transmitter
output power can be set from 1.58 mW to 1.58 W EIRP
when using the internal antenna.
DN-900 series modems are well-suited for serial data net
-
works carrying moderate traffic that need robust communi
-
cations in locations with non-ideal RF propagation and/or
where RF interference or noise are present. DN-900 serial
modems can operate in point-to-point, point-to-multipoint,
peer-to-peer and tree routing DNT900-based wireless net
-
works.
DN-900 data modems are shipped configured to transmit
transparent data, which requires no protocol formatting. All
that is required to set up a transparent point-to-point serial
data link to configure one modem as a base unit using a
simple PC-based utility. DN-900 series modems can also
operate in protocol mode, which is supported by a rich set of
configuration parameters that allow a wide range of network
layouts and configurations to be optimized.
www.RFM.com E-mail: info@rfm.com Page3of5
© 2012 by RF Monolithics, Inc. DN-900 Series - 07/30/12
Figure 1
