Transmitters 9 November 2001 123
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Tran sm it te r
Adjusting the DT-QTX Fiber-Length Setting
(810-QTX only)
The 810-QTX may be used for any link up to 150 km. Adjust
the 810-QTX for link length as follows:
It is not necessary to connect
fiber to the 810-QTX before
adjusting the fiber-length
setting.
1. Install the 810-QTX and supply power.
2. Check voltage at the fiber test point.
3. Convert voltage to kilometers:
1 V at the test point = 10 km.
4. Turn the fiber-length adjustment potentiometer and
monitor voltage at the test point until the number of volts
corresponds with the actual link length.
• Turn clockwise to increase voltage for longer fiber
length.
• Turn counterclockwise to decrease voltage for
shorter fiber length.
Voltage readings (in parentheses) are taken at the Fiber Test
Point. Factory settings are ± 5 km (0.5 V).
Removing a Module
Remove a transmitter from the shelf as follows:
1. Turn laser key switch counterclockwise to turn off the
laser. The LASER LED goes out (dark).
2. Lower the fiber-management tray by pulling down firmly
on the tray’s front panel.
3. Unplug the fiber.
4. Install the cap in the bulkhead.
5. If you plan to leave the slot empty, disconnect the RF
input cable(s). Use a 75-ohm, F-type terminator to
terminate each cable. If you plan to fill this slot, do not
disconnect input cable(s).
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