61200062L1-1 DSU 56/64 User Manual 3-1
Chapter 3 Test Modes
In addition to a self-test mode, the DSU 56/64 has other extensive
test modes which are designed to help isolate problems to specific
components of the communications circuit. These various test
modes for the DSU 56/64 are initiated and terminated from the
front panel using the SELECT and TEST buttons.
SELF TESTA self-test goes through the following cycle.
1. When the DSU 56/64 is powered on, all LEDs on the front
panel turn on simultaneously for approximately two seconds.
2. After two seconds, all the LEDs turn off briefly.
3. The LEDs then cycle on in pairs with a fan-out pattern away
from the ALM indicator.
4. Next, the LEDs cycle off in pairs with a fan-in pattern back
towards the ALM indicator.
These patterns are repeated four times for visual verification that
all LEDs are functioning properly.
At the completion of the LED test patterns, the PTRN LED is on,
which indicates that the DTE with TP test is being performed.
If the test is successful, the ERROR indicator does not turn on.
If the DTE WITH TP test fails, the RS, ALM, DTE, PTRN, and ERROR
indicators all flash.