Serial Control Mode - RDT RM96xx User Manual

Serial Control Mode

Introduction
Selecting Serial Control mode permits various Radio Modem parameters to be interrogated and modified
via the serial port instead of using the on-board DIL switches.
In some applications the user equipment takes care of addressing in which case an RM96xx operating in
one of the standard modes can be utilised to provide a straight forward transparent serial data link.
In applications where the user equipment is not addressable, the address of the base station RM96xx will
need to be changed to enable communications with remote units that are set to unique addresses. In
applications such as this, Serial Control provides the solution.
FIG. 1 Example System Configuration
Operational Overview
A typical configuration is detailed in Fig.1 above. Basically, in a polled system with one master
unit and several remote units the system operates as follows;
Each remote unit is a standard RM96xx with a unique address and/or RF channel set via the
on-board DIL switches.
The master unit is set to operate in Serial Control Mode. It receives ASCII text strings from the host in a
simple format which specify or interrogate it's address or RF channel number.
The master unit responds to the host with a reply string confirming the action or containing the value of the
address/RF channel number currently set.
Serial data is transferred until a command is received to change to another address or RF channel.
In this configuration the master station can only listen to one remote station at a time. This is not a problem
when using a polling system because the radio modems communicate with each other in pairs.
Global Addressing
Global addressing may be selected from software versions 2.4 (RM9600) and 2.5 (RM9634) onwards. This
function allows a broadcast message to all stations in systems operating under serial control where
messages are normally directed to a specific selected station. It is activated by sending the serial control
command to select address 255 to the master station or any station that must broadcast to all others on the
system.
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