Fluke TS 1200, User Manual

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2-9
Using POTS Mode
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Caution
When testing circuits that are close to a battery source, the pops in the
handset receiver that result from clipping onto a line may be quite
loud. Although there is protection against acoustic shock built into the
test set, if the receiver is held tightly against the ear, acoustical shock
may occur. The TS1200 Test Set is designed to rest comfortably on the
shoulder with the receiver away from the ear. It should be used in this
position when working close to a battery source.
Talk Mode
When switched to Talk mode, the TS1200 goes off hook and draws dial tone. When off hook,
the test set operates like a standard telephone; it is typically used to verify the proper operation
of a voice telephone line or to establish temporary communications on a “borrowed pair”.
Data Lockout
During the transition between Monitor and Talk modes, a sub-mode may be entered if data is
present on the line. This sub-mode is referred to as Data Lockout mode. In the Data Lockout
mode, the unit is kept on hook, or locked out, despite having been switched to Talk mode. Data
Lockout mode is provided to help prevent accidental corruption of a data transmission while
working on the lines. The lockout may be overridden and the test set taken off hook, despite
the presence of data, if the user desires to.
Note
When the TS1200 ADSL modem is active, data lockout will not occur.
Data Lockout Override
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 accessing POTS on a subscriber line that carries both ADSL and POTS.
Telephone lines near AM radio broadcast facilities, pick up the RF signals from the broadcast
antennas. Normally this isn’t a problem for the TS1200. If the line is well balanced, the TS1200
will not see the RF signal because it is a common mode (longitudinal) signal. But if the line isn’t
well balanced, a portion 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 TS1200. If you
know for sure you are on such a line, use the unit’s override capability to go off hook.
Note
Lockout override can be activated only when the test set is locked out.