8
TS25D Test Set
Users Guide
Going off-hook on a line carrying a high dc voltage can
damage the power supply feeding the line. The test set
will prevent this from occurring. Unlike the data
lockout, there is no provision for the operator to
override a high voltage lockout. Lines with voltages
exceeding 140 Vdc do not carry analog voice services. If
you encounter a high voltage lockout, switch the Talk/
Monitor switch back to Monitor (
M
) and carefully
remove the test leads from the line.
Low Voltage Lockout
Each time the test set is switched to Talk mode, it tests
the line for high-speed data signals and it measures the
DC voltage on the line before it goes off-hook. If there
is less than 3 V on the line, there is not enough voltage
for the test set to go off-hook and the LCD will display
LOW VOLT LOCKOUT, DOWN ARROW FOR TALK
BATTERY
.
The Low Voltage Lockout message indicates that there
is very little or no voltage on the telephone line — not
enough voltage for the test set to perform off-hook
operations. The most common cause of this message is
when the test set is switched to Talk mode and it is
either not connected to anything or it is connected to
an un-powered pair of wires (dry loop). In this state you
have the option of activating the test set’s Talk Battery
function.
There is one additional line condition that should be
mentioned. When the test set, connected to a line
carrying data signals but no DC voltage, is switched to
Talk mode, the LCD will display
DATA DETECTED AND
LOW VOLT LOCKOUT
. Some data services have no
associated DC voltage. The low impedance of the
TS25D Test Set’s off-hook state would corrupt these
types of services. Thus the test set does not have any
provision to override the lockout when this line
condition is encountered.
In any of the test set’s lockout states, removing the test
set from the line condition that is causing the lockout
automatically clears the lockout condition.
Talk Battery
The TS25D Test Set can power a dry telephone wire pair
to enable voice communications between itself and
another test telephone connected to the other end of
the pair. After turning on Talk Battery at your end, the
person at the other end should take his test set off-
hook. If the test set at the other end has talk battery
capability, it should not be enabled.
The Talk Battery function provides the following:
•
Communications capability on 26 gauge wire pairs
up to about 1000 feet, longer on larger gauges.
•
A continuity test.
When Talk Battery is active, the LCD displays
LINE =
SHORTED
if the test set is connected to a short circuit of
0
Ω
to about 100
Ω
.
To enable Talk Battery:
1
Connect the test set to a dry pair.
2
Set the slide switch to the Talk (
T
) position.
3
Press the down arrow when the message
LOW
VOLT LOCKOUT, DOWN ARROW FOR TALK
BATTERY
appears.
Note
The Talk Battery function drains the 9 V battery
more quickly than other TS25D Test Set
functions.
