Manual

32
also be used to identify the voltage at the ISDN U interface. Starting at 100 V,
ET720 and ET800 sound an alarm tone to warn of high voltage.
Busy line
Supply voltage between 10 and 20 V DC. LED POL glows darkly. Red: a/b re-
versed; green: correctly polarized. Useful e.g. at a distributor to check wheth-
er the line is busy or not. Alternating call voltage is indicated by the red and
green POL LED lighting up. If the alternating voltage is AC only, the POL LED
lights orange. In general, ET can be used to check any type of voltage source
(max. 90 V) for polarity, to check the type of voltage and its approximate level.
3. Mode DATA – Network Port Test and Port Finder Function (Link Blink
Function) (ET400/ET720/ET800 only)
If the slide switch is set to DATA position, the DATA LED lights up dimly
green as indication. The additional yellow RJ-45 test lead is used for testing.
Plugged into a network port, the green DATA LED lights up brightly in sync
with the normal link pulse signal (NLP) if the network port is patched. The
NLP signal is transmitted every 4 seconds. This is indicates on the ET with a
change in the blinking of the DATA LED and at the ET720/ET800 with a tone
sequence. With the most common hubs, switches, or routers, the LINK LED
belongingtotheportisswitchedonando󰀨intimewiththesignal
2
. This way,
theportassociatedwiththenetworksocketcanbeidentied.
4. Finding and Testing Fiber Optic (FO) Cables (ET800 only)
Theberoptictestusesalaserlightsourcewithvisibleredlight.Thetrans-
mitting power is less than 1 mW (laser class 2).
Warning: Never look directly into the laser beam!
The universal socket is suitable for all common plugs with 2.5 mm ferrule. It
hasabronzespringsothattheferruleisheldrmlyinthesockettoprevent
accidental unplugging. The ceramic material protects the ferrule against me-
tallic impurities.
If required, adapters are available from 2.5 mm to 1.25 mm (Z180A), from
2.5 mm to POF (Z180B) and from 2.5 mm to SMA 905 (Z180C).
Testing Procedure
SwitchontheET800inTONEmode.Nowplugtheberopticcablewiththe
ferrule into the universal socket. To switch on the laser source, press the
SOLID andALT keys together for > 1 s.TheET800 conrmsthe LASER
² Insomecases,theNLPsignallteringmustbedeactivatedinthesettingsofthehub/
router/switch.