ADTRAN 1200410L2, User Manual

Page: 26 / 80

Chapter 2. Installation
26 ESU LT User Manual 61200410L2-1A
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
Appendix B, Pinouts 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
Appendix B, Pinouts 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 electronic components
internal operation 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.