DATU (Direct Access Test Unit)

DATU (Direct Access Test Unit) is a loop conditioning system which is installed in the Metallic Facility Terminal (MFT) frame and connected through a No-Test trunk to a switching facility. DATU is then accessed by dialing a telephone number and following the voice prompts.

DATU Features

DATU features include:

Audio Monitor – The subscriber line may be monitored for up to 10 minutes, after which time the DATU disconnects from the No-Test trunk. Audio Monitor may be used on either busy or idle lines. Traffic on a busy line will be audible but unintelligible. The Audio Monitor Mode may be exited before the end of the 10 minute period by selecting an appropriate test function.

Open Line – The subscriber line is opened by removing battery and ground.

Short Line – A metallic short is placed across the tip and ring of the subscriber line.

Short To Ground – Establishes a metallic connection between tip, ring, and ground. This feature is not available on a busy line.

Tip To Ground – Establishes a metallic connection between tip and ground with the ring open.

Ring To Ground – Establishes a metallic connection between ring and ground with the tip open.

High Level Test Tone – This is a high level, 577Hz, metallic-tracing tone, and is interrupted four times per second for identity purposes. This feature is not available on a busy line.

High Level Tone On Tip – Test tone is placed only on the tip side of the line, with the ring side grounded.

High Level Tone On Ring – Test tone is placed only on the ring side of the line, with the tip side grounded.

Low Level Test Tone – This is a low level, 577Hz, simplex-tracing tone that will not disturb traffic on a busy line. The tone is interrupted four times per second for identity purposes and may be applied even if the line under test is busy. Note that on some No.5 ESS switches, Simplex tone may not transmit.

Single Line Access – Allows conditioning functions on the same line used to access the DATU system.

Hold – Used to continue a line preparation function after disconnecting from the system’s access line.

Forced Disconnect – Allows the technician to disconnect from the system at any time by dialing ##.

Administrative – Password protection for both user and administrator modes of access. System usage counters and timers are accessible through interactive voice response.