Manual

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the Probe is moved evenly above them while pressing down the LOW button.
If the test tip of the Probe is now led over the wires, a high level is displayed
overtherstwireofthecorrectwirepair,aminimumlevelinthemiddle,and
ahighlevelagainoverthesecondwire.Thisidentiesthepairexactly.Ifno
minimum can be found, it is either the wrong pair of wires or there is a cable
fault, e.g. caused by an interruption, an exchange, or an overcurrent (what is
called a split pair).
The ET sends the search frequency with approx. 12 dB also into cables/lines
withaterminatingresistordownto50Ω.ThuswiththeET,asearchtonecan
also be sent to telephone or data lines carrying supply voltage. The maximum
cable/line/wire length is 15 km (unloaded).
2. Mode CONT – Continuity and Resistance Testing
If the slide switch on the right side of the ET set to CONT, the continuity test
mode is activated. A test voltage is applied to the test lead. This way, the continu-
ityofcables,lines,contacts,wires,orresistorsupto100kΩcanbetestedeasily.
ThegreenCONTLED ashesbrieywhenthetesthasbeenactivatedor
whentheresistanceatthetestterminalsexceeds100kΩ.Itlightsupfrom
bright to dark, depending on the value of the resistor. This allows an approx-
imate determination of the resistance. In case of EDP cabling, determining
whether the cable is patched is thus easy and interference-free.
The ET720 and ET800 have an additional sound test mode built in. This
replaces what is called a "beeper". The frequency of the tone depends on the
resistance.At0Ω(shortcircuit)approx.3kHzandatapprox.100kΩ500Hz
are audible. This makes it possible to estimate resistance values. But capac-
itors and other components can also be easily tested in this way.
Fast display of line status
Forlivedatalines/cables(90Vmax.).TheETishigh-impedance(~10MΩ).
The cable/line therefore will not be loaded. The status of the connection ca-
ble, for example, is displayed immediately after switching on and plugging the
ET into the connection socket. How the ET is connected depends on the de-
vice variant, e.g. directly with the RJ-11 plug, or with the optionally available
TAE adapter or by simply connecting to the wires using the crocodile clips.
Free line
Supply voltage up to 90 Volt DC (ISDN). The LED POL lights up and its intensi-
ty depends on the voltage level. Red: a/b reversed; green: correctly polarized,
A wire or minus on red terminal. The ET additionally indicates with a bright red
POL LED that the voltage on the test leads exceeds 90 V. This information can