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The controls of the TDR have been arranged such that the
instrument is easy to use. The instrument controls consist of
the following:
1) L1 Sockets:
The sockets are designed to accept the leads supplied with the
instrument, or the optional mains blocking filter. Line 1 is
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Features and Controls
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usually connected to the faulty line or the line under test. In
Xtalk mode, this is the transmitting terminal.
2) Contrast:
This is a rotary control that lets the user correct the display
contrast for user preference and adjust for the extremes of
temperature.
3) Balance:
This is a rotary control that allows the user to match the
impedance of the internal balance circuit to that of the cable
under test. When balanced, the transmitted pulse can be nulled
out and cable features close to the leads can be detected.
4) L2 Sockets:
The sockets are designed to accept the leads supplied with the
instrument, or the optional mains blocking filter. They allow a
second cable to be tested simultaneously for direct comparison
or are used on a known good line to null out the transmitted
pulse instead of using the internal balance circuit. In Xtalk
mode, this is the receiving terminal.
5) Instrument Display:
The display shows the user the current settings of the
instrument and the reflected energy trace from the cable(s)
connected. It can also display the menu and help screens and
stored traces.
6) Cursor Left:
This control moves the cursor left or, if in a menu screen,
selects a lower value.