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58 Chapter 3: Assembling and Cabling the WAN Components

The system LEDs are PWR and OK. They are fairly self-explanatory. The PWR LED should
be green if the router is powered on. The OK LED should be green if the router has passed the
POST. The OK LED flashes during the router boot sequence.

The BRI interface LEDs consist of one LED for each B channel (B1 and B2). Each is green
only when that B channel is connected to a remote site.

There are two WIC LEDs. The CD LED is green once an active connection is established on
the serial interface. The ACT (Activity) LED is green once traffic is detected on the WAN
interface. On the back of the router, the WIC itself has an LED (CONN) indicating that data is
traversing the link.

SOHO Router Verification

These routers are generally quite small. Many of them are not much larger than the old Hayes
and US Robotics modems of the 1980s. There is only so much that can be said about LEDs
before the point is over emphasized. As in the two previous sections, this discussion focuses on
a single router chassis, in this case, the 770 router. Figure 3-6 depicts the LEDs in this
discussion.

Figure 3-6

770 Router LEDs

As you can see in the figure, there are a number of LEDs on this box. Table 3-2 analyzes the
relevant LEDs, from left to right.