User's Manual

DRAFT - CISCO CONFIDENTIAL
3-6
Cisco Aironet 1400 Series Wireless Bridge Hardware Installation Guide
OL-4072-01
Chapter 3 Mounting and Alignment Overview
Aligning the Antenna Using the RSSI Voltage
When using LEDs to maximize the signal, you adjust the antenna until as many LEDs as possible are
turned-on and the rest are blinking as fast as possible.
Aligning the Antenna Using the RSSI Voltage
The RSSI port outputs a DC voltage that is proportional to the received signal level. The RSSI voltage
is available whenever a signal is present, regardless of the bridge mode (installation or normal),
association status, or pre-configuration role setting. The RSSI voltage provides an instantaneous reading
as you move the antenna. The RSSI port is a female BNC connector on the bridge housing (see Figure 1).
The RSSI voltage increases linearly with signal level as shown in Table 4.
Note A larger RSSI voltage reading indicates a stronger signal.
The voltage varies from 0 to 2.7 volts for signals between -90 and -20 dBm, respectively. The accuracy
over temperature and component variations is ± 4dB. To obtain RSSI readings, you can use any
convenient voltmeter connected to the RSSI port using a cable with a male BNC connector.
1. Slow blinking rate of 1 Hz/sec.
2. Medium blinking rate of 2 Hz/sec.
3. Fast blinking rate of 4 Hz/sec.
Table 4 RSSI Voltage Levels
Nominal Signal Level (dBm) RSSI Reading (volts)
-20 or greater 2.70
-30 2.31
-40 1.93
-50 1.54
-60 1.16
-70 0.77
-80 0.39
-90 or less 0.00