AT&T 7400B Plus User Manual page 11

DEFINITY Communications System
7400B Plus Data Module
User´s Guide
Connector
POWER/
TEST
DATA
METERING
AA
CD
RD
SD
TR
OH
CHECK
SPEED
DATA
Front Panel LED Indicator Descriptions
Description
This red LED normally indicates that power is applied to the 7400B Plus.
This LED flashes during any test mode, except the start-up self-test. It
also flashes along with the DATA LED when the 7400B Plus is unable to
communicate with the PBX.
This red LED indicates that the Data Metering option is enabled, and will
indicate the state of the CTS (Clear To Send) lead when metering.
Automatic Answer. This red LED lights continuously when Automatic
Answer is enabled, and flashes when there is an incoming call.
Carrier Detect. This red LED lights as long as communication is
established with the far end device.
Receive Data. This red LED lights when received data is being
transferred from the 7400B Plus to the local terminal device.
Send Data. This red LED lights when transmitted data is being
transferred from the local terminal device to the 7400B Plus.
Terminal Ready. This red LED normally indicates the state of the DTR
lead. The LED is always on when the 7400B Plus is optioned to ignore
the DTR lead.
Off Hook. This red LED lights continuously from the time a data
communications call is initiated until the call is terminated.
This red LED lights when a call set up fails because of an incompatibility
between the configuration of the local terminal device and the far end
device. The incompatibility will usually occur if a common operating
speed cannot be achieved between the two endpoints. Chapter 5,
"Troubleshooting," provides information about this and other conditions
that may cause this LED to light.
This green LED lights to indicate that a data call is in progress. This LED
flashes along with the POWER/TEST LED when the 7400B Plus is unable
to communicate with the PBX.
TABLE 1-1
CHAPTER 1: INTRODUCTION
Page 1-5