RTU-292C Operations Manual
5-3
Figure 5-1
Hybrid Balance Test Set-Up
5.5.2.1
Main Hybrid Test Procedure
1. Disconnect the RTU-292C from all other equipment and connect the test equipment as shown
in Figure 5-1.
2. Set the PSTN levels for -9 dBm using Option SW2-1, -2, and -3.
3. Start with the following pushbuttons OFF: TEL LINE/PHONE, TEL LINE/RADIO, and TEL
VOX. The positions of the other buttons are unimportant. Place the RTU-292C in set-up mode
by setting SW2-7 ON and then turning on the power. (See Section 2.10.1 for further details about
set-up mode.)
4. Adjust the TX Level Adjust, R133, so that the audio voltmeter reads -6dBm (0.387V rms).
This sets the transmit signal output path in the RTU-292C for unity gain if the input level is
correctly set.
5. Adjust the RX Level Adjust, R116, so that the PEAK LED flashes rapidly and is on about 50%
of the time. (This is different from the instructions in paragraph 2.10.3, which set the RX Level
Adjust for voice)
6. Remove the unit from Set-up Mode by turning the RTU-292C Main Power OFF, setting SW2-
7 OFF, then turning the main power back ON.
7. Push the TEL LINE/RADIO button to start the adaptation cycle.
8. When the initial adaptation cycle is complete, the noise output can be read on the audio
voltmeter. The voltage should be less than -37dBm (10.9 mV). The trans-hybrid loss is the
difference between this reading and the approximate -7 dBm noise level.
Summary of Contents for RTU-292C
Page 4: ...RTU 292C Operations Manual 4 Blank Page...
Page 12: ...RTU 292C Operations Manual 12 This page intentionally left blank...
Page 35: ...RTU 292C Operations Manual 2 17 Figure 2 1 Outline Dimensions...
Page 37: ...RTU 292C Operations Manual 2 19 Figure 2 3 Location of Internal Option Settings...
Page 38: ...RTU 292C Operations Manual 2 20 Figure 2 4 Internal Option Settings Details...
Page 39: ...RTU 292C Operations Manual 2 21 Figure 2 5 Audio Interface Wiring Diagram...
Page 40: ...RTU 292C Operations Manual 2 22 Figure 2 6 Interface Details...
