VeEX VePAL TX300M, User Manual

Page: 232 / 421

feature. Select the appropriate loopback command set by pressing on the corresponding check box. Testing interfaces allow the
user to troubleshoot problems and to check the quality of links at the T1 Layer.
DS1 Loop
Select the loopback command set.
Note:
In-band, ESF DFL, and HDSL Abbreviated Loopbacks functions allow only one element in loopback mode. Loop down any
previous element before addressing a new one, or else a warning message "Error - Pre-existing loop found" will display.
In-band
Use this mode to loop up and loop down CSU and NIU using in-band loop codes.
Loop up
sends the loop command and
Loop
down
sends the release command. This function will only allow one element in loopback mode.
ESF (Out-of-band)
Uses the Extended Super Frame Facility Data Link control to send a repeating 16-bit ESF data link code word to the remote end
requesting a Payload or Line loopback. ESF FDL loop codes require T1 framing to be set as ESF, otherwise the items will be
grayed out.
HDSL Abbreviated Loopbacks (Short)
Also known as short loop codes, HDSL abbreviated loopbacks are used to loop specific network elements of a compatible line,
including CO, repeaters, CPE equipment and line cards. Users must select the location from which the test is to be conducted
(CO/Network or CPE), select the network element to be addressed and send the Loop up or Loops down command. The white
arrow is used as a visual indicator to remind the user in which direction the codes are being sent.
HDSL In-band Loopbacks (Long)
Also known as long loopback codes, HDSL in-band loopbacks are a more complete loopback system that uses 16-bit code-
words to loop specific network elements and provide confirmation and status. These confirmations are based on burst of errors
sent back to the test set and the number of errors sent depend on type of confirmation and meaning. The status pop-up
messages will show the meaning of those confirmation “codes” and the respective number of errors in brackets; for example:
[111] indicates “Attenuation and Margin OK." See HDSL2 and HDSL4 Command Reference Table for code meanings.
User must select the type of HDSL cards being tested (2-wire vs. 4-wire), the location from which the test is to be conducted
(CO/Network or CPE), the network element to be addressed, and the Loop up or Loop down command.
Before sending any loop command, the line must be armed, otherwise loop commands will be ignored. When the user enters the
function, the GUI will only show commands to Arm the link, loop down any element previously looped up, or disarm an already
TX300S_e-manual_D07-00-064P_RevA00