Cabling the Metallic Loop Test Access Ports 4-17
920550-5020 Rev 14 HN4000 Hardware Installation Guide
4.7 Cabling the Metallic Loop Test Access Ports
TheHN4000providesexternaltestaccessto2BASE‐TLcopperloopsviatwoMetallicLoop
Test(MLT)RJ‐45jackslabeled“OUT”and“IN”(Figure 4‐12)
TechnicianscanusetheMLTtopre‐qualifycopper‐loopspriortoturn‐up.Akeybenefitof
usingtheHN4000switch’sMLTport
isthatitensuresend‐to‐endconnectivityfromtheswitch
totheattachedCPEdevice.RefertotheHN4000UserGuideformoreinformationaboutcopper‐
pairtestingwiththeMLT.
4.7.1 MLT-Port Cabling for Line Tests
TheHN4000switchhasaninternaltestbusthatprovidesconfigurableconnectionsbetweena
2BASE‐TLPMEandtheMLTtestports(Figure 4‐12).
Figure 4-12 Metallic Loop Test Ports
Table4‐6showstheMLTports’pinassignments(whichapplytoboththe“IN”and“OUT”
ports).
Byusingaline‐test’sconfigcommand,youspecifywhichPMEtoconnect totheswitch’sMLT
“IN”testport.Forexample,thecommandconfigmltset2bpme3/21connectsPME21on
switch3totheswitch’sMLT“IN”port.
Whenswitchesareinastack,youcanconnectthe“IN”MLTtothe“OUT”portofanother
switchtochaintheMLTportstogether(asdescribedinthefollowingsection).
Table 4-6 MLT IN and MLT OUT Pin Assignments
Pin Position Signal
4 Tip
5 Ring
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