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3. INTRODUCTION
Teletech’s TX916 Loop-a-Line consists of two battery operated
devices known as the PROBE and the OSCILLATOR. Together
these devices are used by the communication technician to aid in
telephone installation and cable fault location and repair.
A communication technician can work unassisted by remotely
controlling an OSCILLATOR (located at the exchange MDF or
street cabinet) from a PROBE located on the same line up to 20km
away. This eliminates multiple journeys along the cable path and
dramatically cuts repair and installation costs.
Operating modes:
•Pair identification
•Disconnect/connect service to the exchange
•Open circuit pair
•Short circuit pair (with or without white wire)
•Insert 600 Ω line termination.
When a Loop-a-Line is used in conjunction with a Resistance
Bridge or TDR instrument; loop, insulation resistance, resistance
balance measurements and fault locating can be performed.
3.1. BATTERY REPLACEMENT
Both devices are powered by a 9 V alkaline battery (IEC 6LR61)
which can be inserted or removed by removing the battery lid on the
rear of the device using a flat head screw driver. Orient the battery
according to the polarity diagram within the battery compartment.
WARNING: Disconnect all test leads before removing the
battery lid to avoid possible connection to high voltages
sometimes present on telephone lines.
3.2. TEST LEADS
The OSCILLATOR and PROBE each have their own test leads
which are inserted into their sockets (see Figure 1-1).
Next to the PROBE’s test connector (see Figure 1-2) is a 3.5mm
audio jack that allows earphones to be inserted and is useful when
performing Pair Identification in noisy environments.
WARNING: Due to large voltage spikes sometimes
present on telephone lines, don’t insert the earphones
when the PROBE’s test leads are connected to the line.
