Diagnostic Parameters and Commands
Using diagnostics-related VT100 commands
MAX Administration Guide
B-13
To initiate a loopback test on the first T1 line, highlight Line LB1 and press Enter. After
prompting for confirmation, the MAX starts the loopback test and the Alarm LED lights up.
When you exit the menu option, the MAX automatically deactivates the loopback.
For related information, see the FDL parameter in the MAX Reference.
Line LB2
Line LB2 is a Line LoopBack command for Line 2 in a T1 slot. When you start the line
loopback test for a T1 line, a remote device can test the T1 line and the MAX unit’s interface to
the T1 line. All signals received by the MAX are looped back (behind the MAX unit’s CSU
repeater or DSX signal-conditioning module) toward the remote device. The remote device
can determine the quality of the T1 line by comparing the sent signal to the received signal.
Line LoopBack (LLB) occurs behind the MAX unit’s CSU repeater or DSX
signal-conditioning module. Drop-and-Insert channels are also looped back. Do not activate
LLB when a call is active on the line. Doing so disrupts the data flow between the codecs
connected to either end of the network line. The MAX responds to both the inband LLB signal
and the Facility Data Link (FDL) LLB message. Therefore, a management device can put the
MAX into LLB. A management device is a unit, on a T1 line, that measures the line’s
performance and can send management signals to other devices on the line.
To initiate a loopback test on the second T1 line, highlight Line LB2 and press Enter. After
prompting for confirmation, the MAX starts the loopback test and the Alarm LED lights up.
When you exit the menu option, the MAX automatically deactivates the loopback.
For related information, see the FDL parameter in the MAX Reference.
Switch D Chan
The Switched D Chan command swaps the status of the primary and secondary NFAS D
channels. It applies only to T1 lines using NFAS signaling.
Clr Err1
The Clr Err1 command clears the user error event register of Line 1, but does not clear the
performance registers for the line. To clear all performance registers for Line 1, use Clr Perf1.
To clear all performance registers for Line 2, use Clr Perf2.
Note:
Error events have no meaning for D4-framed lines. A D4 line uses the Superframe
format to frame data at the physical layer. This format consists of 12 consecutive frames
separated from one another by framing bits.
Clr Perf1
The Clr Perf1 command clears all performance registers for Line 1, restarts the current time
period, and begins accumulating new performance data.
For related information, see the FDL parameter in the MAX Reference.