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MOTOROLA
1. OVERVIEW
The VRM 500 (Vehicular Radio Modem) is designed to
interface Data Terminal Equipment (DTE) with Motorola
mobile radios for access to Motorola DataTAC mobile data
networks.
The DTE can be either a laptop computer, a terminal
supporting industry-standard Hayes® AT commands, or a
peripheral requiring a specific application firmware.
The radio data network infrastructure is comprised of a host
computer, base interface equipment and base stations (see
Figure 1).
The Radio Network Controller (RNC) performs message
routing between the DTE and the host computer. The RNC
serves to translate
host
transmitted
messages
into
GENERAL DESCRIPTION
proprietary signaling format, and convert received messages
in the signaling format to the appropriate host protocol.
The DSP technology enables the VRM 500 to support the
following RF protocols: MDC-48oo, MMP-30/31, RD-LAP
9.6/19.2 kbps.
The VRM 500 incorporates the following key features:
• Receive and store incoming messages ability even
while disconnected from DTE.
• A rechargeable, internal lithium back-up battery to
preserve the modem's random-access memory (RAM)
for up to ten days when the main power is removed.
• Visible status indicators (LEDs).
• Capability to operate with both parallel and serial
interface schemes.
BASE STATION
\
~70
©
Motorola Inc., 1995
Figure 1. Typical Configuration
Land Mobile Products Sector
1301 E. Algonquin Road, Schaumburg, IL 60196
68P02943C71-0
July, 1995
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