Specifications

Chapter 3 Testing & Diagnostics
3-1
TESTING & DIAGNOSTICS
DIAGNOSTIC SWITCHES
There are 4 slide switches on the Access Bank front panel to
enable test functions, along with a test tone switch and T1
monitor jacks.
Self Test Switch
Note: The LIU card and at least one channel card must be in place for a valid
self test. (Please allow at least 16 seconds for self test results. A RED
indication on the TEST LED may be seen for 16 seconds after self test
is initiated for some signaling options. This is normal. After the 16
seconds of trunk processing, the RED TEST LED should turn to green.)
Setting this test switch to the Self Test position loops the T1 signal
transmitted by the Access Bank back toward the Access Bank internally. The
incoming T1 network line is automatically disconnected from the Access Bank
during this test. This equipment loopback function is performed internally by
a relay at the T1 line connection point of the Access Bank - assuring that all
of the Access Bank circuits and protection devices are included in the self test.
The self test also allows the user to receive ringback at the Tip and Ring
connection so that a butt set or telephone can be attached at the punch down
block for the receipt of ringback.
The Self Test operation results in the ringback tone being received on all 24
channels from the internally looped T1 signal. Thus ringback tone can be
heard on all 24 channel Tip and Ring interfaces with a telephone or test set. If
the ringback tone is not heard on a channel, a problem is indicated with the
audio path of that channel. See the diagnostic trouble shooting section if you
experience this problem.
The Test LED indicates the results of the Access Bank self test as follows:
Green: Self Test Switch Activated, LIU T1 Self Test Passed:
T1 Signal Received, In Frame (ESF or SF as configured), Proper Line
Code Received, no ESF or BPV errors received.
Red: Self Test Switch Activated, T1 Self Test Failed due to one or more of:
T1 Loss of Signal, Out of Frame, Improper Line Code Received, ESF
or BPV errors received, or Framer Write/Read error. A Red Self Test result indicates that the
Self
Test
Normal
Normal
Normal
Normal
Network
Loopback
Alarm
Cutoff
Test
Status
T1
Framing
Input
Monitor
Output
Monitor
T1
-48Vdc
Return
Ground
Tip & Ring
Test Tone
Switch #7
Self Test
Switch
Diagnostic
Switches
Network Loopback
Switch
Normal/Remote
Alarm Cutoff
Switch
Test, Status
T1 Line &
Framing LEDs
T1 Monitor
Jacks