Fluke TS53 PRO, Руководство пользователя, Страница: 18 / 38

14
TS54TDR/TS53 PRO Test Sets
Users Guide
Be careful not to short the test leads together when
connecting to a data line (or any line for that matter),
as this could bring down the service.
Put the test set in Monitor mode when you use other
instruments to troubleshoot a line.
Data Lockout Override
Normally, when the test set detects data, it means the
operator has accidentally connected to a high-speed
data line and should immediately disconnect from the
line to avoid disrupting the data service.
But in some cases the operator must go off-hook on a
specific line even though the test set indicates that the
line is a data line.
The following are scenarios where the operator may
wish to override a data lockout:
•
When there is false data detection due to RF
pickup on a line that is near an AM radio
broadcast antenna. The RF induced in the line may
appear to be data.
•
When performing a ground start, the test set may
lock out in Talk mode. This is because ground start
lines are unbalanced before startup and thus are
prone to picking up a lot of noise which may
appear to be data to the test set. If this occurs, use
the override function to go off-hook on a ground
start line.
Telephone lines near AM radio broadcast facilities pick
up the RF signals from the broadcast antennas.
Normally this is not a problem for the test set. If the line
is well balanced, the test set will not see the RF signal
because it is a common mode (longitudinal) signal. But
if the line is unbalanced, part of the RF signal will be
converted to a differential (metallic) signal. If the signal
amplitude is high enough, it may be detected as high-
speed data by the test set. If you know for sure you are
on such a line, use the override function to go off-
hook.
You can override the data lockout only in
P
mode.
To activate the override, press
$
. If dc voltage is
present, the test set goes off-hook. To go back on-
hook, unclip the test set’s test leads from the line or put
the test set into Monitor mode.
High Voltage Lockout Operation

Warning

Voltage above 140 V dc, is possibly
dangerous to you and the test set. If the test
set shows voltage above 140 V dc, carefully
remove the test leads from the line. Be sure
to hold the clips by their insulated boots and
do not touch the metal parts of the clips. Do
not touch the clips together while they are
connected to a line that has high voltage.
The TS54 TDR and TS53 PRO are designed for use by
Outside Plant and Central Office technicians in
environments where analog voice lines co-exist with
lines that carry high dc voltage.
Accidentally going off-hook on a line carrying a high dc
voltage can damage the power supply feeding the line.
To prevent this, the test set has an automatic, high-
voltage lockout function. When a test set is in Talk
mode and is connected to a Tip and Ring pair, it
measures the voltage on the line before going off-
hook. If the measured voltage exceeds 140 V dc, the
test set locks out and does not go off-hook. The display
shows
LOCKOUT HI VDC
.
In the event of a high voltage lockout, press
Q
, and
carefully remove the test set leads from the line.
Dialing and Storing Numbers in Memory
Last Number Redial (LNR)
To redial the last number you dialed since you turned
on the test set, go off-hook then press
L
.
If the test set goes off-hook, and you press any dialing
key, the LNR memory is deleted and the key is stored as
the first digit in LNR memory.
The dialing keys that are stored in LNR memory are
1
2 3 4 5 6 7 8 9 $ +
. The star (
$
) and pound (
+
)
keys are not redialed when the test set is in pulse
dialing mode even if the redial memory includes them.