TD060100-0MA
20
Indicator Lights and Booting
STATUS:
At power on, this LED briefly glows
red
as a test. Then
while Linux boots (about 16 seconds), it
flashes green
. It then glows
solid
to indicate Linux is operational — although another 16 seconds
must pass before ARCNET is functional. If this LED glows
red
during
normal operation, a power supply problem is indicated; if the external
power source is within specification, the JC-MER-CXB needs service.
ARCNET:
If the unit is
connected
to a working ARCNET network,
the “RX” LED glows green whenever the unit receives data — otherwise
the “RX” LED will remain unlit. If the unit is
disconnected
from the
network, the “RX” LED will glow by default. The “ACT” LED flashes
yellow whenever the JC-MER-CXB is
engaged
in ARCNET activity.
Ethernet:
After 2–3 seconds into the boot process (and thereafter), the
“LINK/ACT” LED will glow if a
valid link
exists to an working Ethernet
device. It indicates speed by
color
:
green
for 100 Mbps and
yellow
for
10 Mbps. It
flashes
to indicate activity. The “DUP” LED glows
green
to
indicate full-duplex operation and
yellow
for half-duplex.
Bash Prompt and JC-MER-CXB Commands
The JC-MER-CXB uses the Linux operating system. When the Linux
command line is displayed on screen, a special "bash" prompt appears.
Because it is derived from the
Bourne
shell, the prompt is known by
the pun:
B
ourne
A
gain
Sh
ell, or
bash
. It is the standard command-line
interface on most Linux machines. All command-line entries for the
JC-MER-CXB must
use lower case letters
!
The bash prompt for the
JC-MER-CXB is shown below.
Figure
13
—
Bash Prompt for the JC-MER-CXB