You can use this screen to perform loop back testing on a digital trunk.

Information Displayed

• Loopback Status
  You can use this drop-down to show and set the type of loopback applied to the currently selected channel or channels. The options are None , Payload , Line and Line (Anti Jitter) .
• Admin State
  You can use this drop-down to show and set the Admin State of the currently selected channel or channels.

• Changes made using System Status only apply to the channel whilst running System Status. They do not override the system configuration settings.
• To perform loopback testing, select Whole Line and set the Admin State to Out of Service . The changes applies to all channels.
• Selecting Whole Line and setting the Admin State back to In Service returns the status of each channel back to their current configuration settings.

• Test Type
  You can use this drop-down to select the type of loopback testing used. The options are Pseudo-random 15 bit or Pseudo-random 20-bit .

The table lists the individual channels provided by the trunk. Selecting a particular channel allows you to change the change the settings of the channel and perform loopback testing on that channel. The Whole Line row allows you to perform the same action on all the channels at the same time.

• Channel Number
  The individual channel number.
• Call Ref
  The call reference of the current call on the channel.
• Admin State
  The admin status of the individual channel. See above.
• Loopback Status
  The loopback status of the individual channel. See above.

Buttons

The following buttons can appear on this screen:

• Call Details
  Displays call details for the selected call, trunk or trunk channel.

• Disconnect
  Clears the current call. The button cannot stop alerting calls on Loop Start, T1 Loop Start and T1 Ground Start lines.

• Inject Error
  Insert an error into the digital trunk during a loopback test.

• Reset Trunk
  Reset the selected digital trunk.

• Start Test
  Start loopback testing on the trunk. You can only start testing when the Whole Line is set to Out of Service . When testing starts, the test results appear below the list of channels. During the test, the button label and function changes to Stop Test .

• Stop Test
  Stopt loopback testing on the selected trunk. The button label and function changes to Start Test .