Raven 40710D-600, Руководство пользователя

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CHAPTER 5 TROUBLESHOOTING and ALIGNMENT
Troubleshooting and Alignment Procedures
(cont.)
5. Insert the 41675 SNI module into the Extender Card.
6. Turn power ON (flip the toggle switch to the left).
7. Connect a DC ammeter in series with the 2-wire SNI line (B4 and B5 on
the terminal blocks) on the rear panel.
8. Establish a call over the 2-wire line to eliminate dial-tone.
9. With a call established on the line, verify a loop current of 20 to 30mA.
10. Connect a signal generator to pins P and R on the 42067 Extender
Card.
11. Set the signal generator frequency to 1KHz at the level specified by
Attachment A.
12. Connect a “floating” AC voltmeter (earth ground isolated at the AC
supply) to pins ‘M’ and ‘N’ (2-wire SNI) on the 42067 Extender Card.
The signal ground side of the AC voltmeter must be isolated from loop
current through a 2
µ
f capacitor.
13. Read the level specified by Attachment A for the 2-wire SNI (OUT).
Adjust R63 on the 41675 SNI module, if required.
14. With the AC voltmeter still connected, connect a “floating” signal
generator (earth ground isolated at the AC supply) to pins ‘M’ and ‘N’
(2-wire SNI) on the 42067 Extender Card.
15. The signal ground side of the signal generator must be isolated from
loop current through a 2
µ
f capacitor. Adjust the signal generator
frequency to 1KHz at the level specified by Attachment A for 2-wire
SNI (IN) as read on the AC voltmeter.
16. Connect the AC voltmeter (terminate, if required, and not “floating”)
to pins ‘U’ and ‘V’ on the 42067 Extender Card. Read the level
specified by Attachment A. Adjust R35 on the 41675 SNI module, if
required.
17. Connect the signal generator (not “floating”) to pins ‘P’ and ‘R’ on
the 42067 Extender Card. Set the frequency to 1KHz at the level
specified by Attachment A. Adjust R24 and switch in various
capacitance values with SW2 on the 41675 SNI module for a minimum
reading on the AC voltmeter.
NOTE: It may become necessary to utilize the Line Build Out (LBO) if a
satisfactory hybrid null cannot be obtained (a reading of –25dBm0 or
less on pins ‘U’ and ‘V’). Adjust R24 and SW2 on the 41675 SNI module
for the lowest possible reading, then add capacitance to the LBO
and readjust R24 until a satisfactory null is obtained.
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