MDS 05-3301A01, Rev. C
MDS 9810 Installation and Operation Guide
25
Limitations of Single-Radio Repeaters
Diagnostics
As of the date of publication, over-the-air diagnostics is not fully sup-
ported in repeater systems. Diagnostic data from these systems may be
unavailable or unreliable. This is particularly true if a repeater radio is
configured as the “root” in a diagnostics scheme (See “Performing Net-
work-Wide Remote Diagnostics” on Page 53.) Better success might be
achieved by picking a standard remote to use as the root.
Data Throughput
Delay
When
TDD
is set to
ON
, there will be a significant delay in data
throughput and an increase in latency (see Glossary of Terms). In gen-
eral, the data throughput will be cut in half, and worst case latency will
increased by two hoptimes.
4.6 Using the Radio’s Sleep Mode
In some installations, such as at solar-powered sites, it may be necessary
to keep the transceiver’s power consumption to an absolute minimum.
This can be accomplished using Sleep Mode. In this mode, power con-
sumption is reduced to less than 30 milliamperes.
Sleep Mode can be enabled under RTU control by asserting a ground (or
EIA-232 low) on Pin 12 of the radio’s
DATA INTERFACE
connector. The
radio stays in Sleep Mode until the low is removed, and all normal func-
tions are suspended. As a status indication, the radio’s
PWR
LED flashes
once every four seconds to indicate that it is in Sleep Mode.
The radio can be “woken up” by your RTU every minute or so to verify
synchronization with the master station. When Pin 12 is opened (or an
EIA-232 high is asserted), the radio will be ready to receive data within
75 milliseconds.
It is important to note that power consumption will increase signifi-
cantly as communication from the master station degrades. This is
because the radio will spend a greater period of time “awake,” looking
for synchronization messages from the master radio.
Sleep Mode Example
The following example describes Sleep Mode implementation in a typ-
ical system. Using this information, you should be able to configure a
system that meets your own particular needs.
Suppose you need communications to each remote site only once
per hour. Program the RTU to raise an EIA-232 line once each hour
(DTR for example) and wait for a poll and response before lower-
ing it again. Connect this line to Pin 12 of the radio’s
DATA INTER-
FACE
connector. This will allow each RTU to be polled once per
hour, with a significant savings in power consumption.
