ADTRAN 1200410L1, User Manual

Page: 26 / 80

Chapter 2. Installation
26 ESU LT User Manual 61200410L1-1B
Control Port Input
The control port input provides an EIA-232 input from a PC
or a modem for control of the ESU LT. You can also use it as a
chain input from another ESU LT or ESU 120e. For more
information, see
Wiring on page 69.
Chain Port Output
The chain port output provides an EIA-232 output to chain
control to other ESU LTs or ESU 120es. For more information,
see
Wiring on page 69.
POWER UP TESTING AND INITIALIZATION
When shipped from the factory, the ESU LT is set to factory
default conditions. At the first application of power, the unit
automatically executes self-tests followed by an initialization
sequence which sets up the unit.
Self-Test
The self-test checks the integrity of the internal operation of
the electronic components by performing memory tests and
by sending and verifying data test patterns through all
internal interfaces. Although actual user data cannot be
passed during these tests, the self-test can run with the
network and DTE interfaces in place, without disturbing any
external interface.
The self-test automatically executes upon power-up. It can
also be commanded from a front panel menu or from the
control port.
In addition to the specified self-tests, background tests are
run on various parts of the internal electronics. These run
during normal operation to confirm continued correct
functioning. The background tests include the following:
• Monitoring the phase-locked loop for lock.
• Standard background network performance monitoring.
Table 2-1 on page 27 explains how self-tests work.