HT instruments М75 - Manual (Page 24)

M72 - M73 - M74 - M75
EN - 22
7. If cabling is not correct, a screen like this
is displayed (NOT OK). Referring to this
example, “FAULT 1/4” means that the
detected errors are 4, of which the first
one is currently displayed. Details on the
detected error are given on the right side:
the couple 1-2 is open. By pressing
FUNC HOLD key it’s possible to run over
the remaining screens and display other
cabling errors (“FAULT 2/4”, “FAULT
3/4”, “FAULT 4/4”). The number of the
remote unit can be not displayed
Identification number
of the remote unit (if
possible to find it)
Number of the
displayed error /
number of the
detected errors
CAUTION
It’s indispensable to select the right type of cable. If UTP is selected although
a STP cable is tested, test results may be not reliable due to the shield
affecting the measurement.
4.11.1. Anomalous cases which may occur during LAN tests
If the voltage present at the terminal is
higher 0.2V the instrument does not
perform the test and emits a sound to
signal the anomalous situation. The
screen beside is displayed.
CAUTION
Before taking any measurement make sure that the circuit under test is not
powered. Connections to phone lines or active networks could damage the
instrument.
4.11.2. SPLIT PAIRS - explication note
A LAN cable contains 8 conductors, twisted two by two thus forming 4 pairs: 1-2, 3-6,
4-5, 7-8. The error “SPLIT PAIRS” consists in the exchange of two conductors
belonging to different pairs. The pin to pin correspondence seems intact, but physically
the conductors of two couples are split. Such interaction hardly affects (or even makes
impossible) the exchange of data at high frequency/speed.
CAUTION
The error condition “SPLIT PAIRS” is verified only when the cable mapping is
fully correct. For a correct detection of such error condition it’s necessary that
the cable under test is at least 1m long.