22
MDS 4790M (MPT 1411) I/O Guide
MDS 05-3628A01, Rev. B
LED Indicators
The basic operation of the transceiver board(s) can be checked by viewing the
LED Indicator panel. The top row of indicators shows the status of the “A”
transceiver board; the bottom row shows the status of the “B” transceiver
board. In a non-redundant master station, transceiver board A is the only radio
installed. On a redundant radio (spare transceiver board and power supply
installed), the references given here apply equally to transceiver board A and
B.
Normally, only the green
ACTIVE
LED (and, in master stations configured for
redundant operation, one of the yellow
STBY
LEDs) should be lit. All other red
LEDs are alarm indicators. If lit, they indicate a potential problem in the radio
system.
Refer to Figure 18 and the text that follows for a detailed explanation of the
LED indicators.
Invisible place holder
Figure 18. LED Indicators
Table 4. Explanation of Front Panel LEDs
LED Name
Color
Meaning When Lit
ACTIVE
Green
Transceiver board (A or B) is the selected unit.
STBY
Yellow
Transceiver board (A or B) is currently in stand-by mode.
(Functional on master station configured for redundant
operation only.)
ALARM
Red
A major or minor alarm event has occurred; use the front
panel’s Active Radio Status screen to list current alarm
events (see page 61).
RX ALR
Red
Difficulty receiving—may be due to an antenna problem,
receiver fault, or other condition causing no or a weak
received signal level.
TX ALR
Red
Transmit circuitry fault.
I/O ALR
Red
A data framing or parity error has occurred over the data
port.
