General Information; Introduction; Physical Description; Specifications - Hitachi ATT-20 Installation, Operation, Troubleshooting

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GENERAL INFORMATION

1.1. Introduction

This manual provides application, installation and maintenance information for the STS
USA Audio Track Transceiver, Model ATT-20.
The ATT-20 is a short-range transceiver operating in the audio frequency range of 12 to
20 KHz. The high frequency range was chosen to provide sharp block definition. The
ATT-20 can be used in applications such as highway crossings, island circuits, switch
lock release and general train detection in non-electrified and DC electrified territories.
In most cases, insulated joints are not required and track circuits up to 300 feet in length
can be realized. Units are available for operation in either shunt mode or series mode
applications.

1.2. Physical Description

The ATT-20 is a single unit transceiver containing separate transmitter and receiver
printed circuit boards, mounted on a common chassis. The chassis is housed in a sheet
metal box. The top cover of the unit is the faceplate to which Association of American
Railroads (AAR) terminal posts are mounted.

1.3. Specifications

1.3.1. Power Requirements

Power Supply Voltage: 9.8 - 15.2 VDC
Maximum Ripple:
Load Current:
Fuse:
Copyright 2019
1 Vpp
600 mA.
3 / 4 Amp fast blow
SM 6299 Rev. 3, March 2019
ATT-20 Audio Track Transceiver
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