5.0 OPERATION
Once you have configured each Model 1180 properly (see Section
3.0) and connected the fiber and RS-232 cables (see Section 4.0), you
are ready to operate the units. This section describes reading the LED
status monitors, power-up and using the built-in loopback test modes.
5.1 LED STATUS MONITORS
The Model 1180 features six front panel status LEDs that indicate
the condition of the modem and communication link. Figure 6 shows
the front panel location of each LED. Following Figure 6 is a description
of each LED’s function.
•
The green “Power” LED glows if power is applied to the modem.
•
The green “Test Modes” LED indicates that the modem is in a test
mode.
•
The “TD” and “RD” indicators blink red and green with data activity.
Red indicates a low RS-232 logic level, green indicates a high RS-
232 logic level. Note: RS-232 devices idle in a
low state, so the
LED will glow red if the connections are correct and the RS-232
device is in an idle state.
•
The “RTS” and “CD” indicators are also tri-state and glows red for a
“low” signal or green for a “high” signal. RTS lights for an incoming
signal on RS-232 pin 4. CD lights for an incoming signal on the
line side, and the resulting output signal on RS-232 pin 8.
5.2 POWER-UP / SYNCHRONIZATION
Apply AC power to the Model 1180 by plugging the separate AC
power adapter first into the rear panel outlet of the Model 1180 and then
into an acceptable AC power outlet. There is no power switch on the
Model 1180: When the “power” LED is glowing steady, the Model 1180
is powered up. Note: Make sure the front panel toggle switch on
both Model 1180s is set to NORMAL.
After both the local and remote Model 1180s are powered up, a
synchronization process must occur between the two modems before a
link can be established. Depending upon a number of factors, this
synchronization process can take
as long as 60 seconds. Any time one
of the Model 1180s loses power (i.e., in a lightning storm), the local and
remote units
must re-synchronize before they can resume data
transmission. Note: If your application cannot tolerate a 60 second
synchronization phase, turn the front panel “Test Modes” switch to
REMOTE and then back to NORMAL to synchronize the units in a
maximum of 250 mS.
When the local and remote Model 1180s are
both powered up, and
are passing data
normally, the following LED conditions will exist:
• PWR = green
• TD & RD = flashing red and green
• RTS & DCD = green
• TEST = off
5.3 LOOPBACK TEST MODES
The Model 1180 offers two loopback test modes to evaluate the
condition of the modems and the communication link. These tests are
activated from the front panel.
5.3.1 LOCAL LOOPBACK
The local loopback test checks the operation of the local Model
1180, and is performed separately on each unit. Any data sent to the
local Model 1180 in this test mode will be echoed (returned) back to the
user device. For example, characters typed on the keyboard of a
terminal will appear on the terminal screen.
To perform a local loopback test, follow these steps:
9
10
Powered Short Range Modem
Made In The USA
Fiber
RS-232 Interface
Power
Model 1180 Single-Fiber Modem
Power
- Remote
- Normal
- Local
Test
Modes
TD
RD
RTS
CD
Figure 6. Front view of Model 1180