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What does a steady green "RDN" indicator light mean?

Hello.  I have been using Adtran FSU Frame Relay Service Units for many years to connect a Multitech DSU to two 8-Channel Multiplech Multiplexers on a leased 56K line. A few times a day the system will go down with the only indicator light being that the "RDN" indicator light on the FSU will show steady green.  The manual is not helpful.  I have tried swapping out units on the remote side with the same result.  I even switched data lines.  Tried other cables.  Only thing I haven't tried is swapping out units on the Host side.  By the time I get to the Host location the conditions goes back to normal.  Thanks for any suggestions.  Neil

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Valued Contributor

Re: What does a steady green "RDN" indicator light mean?

The RDN LED indicates "receive data network" so the FSU is receiving data from the network, but apparently all DTE communication has stopped (TD and RD are for the DTE interface). Therefore there is no more TDN (transmit data network).

Swapping out the HOST side is worth trying, but the indications are that the DTE side at this location is where the problem is.

Thank you,

Patrick

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Re: What does a steady green "RDN" indicator light mean?

Patrick:  Thank you much for the response.    So  "...indications are that

the DTE side at this location is where the problem is."  means that there

might be a problem with my 8-channel mux's?  Usually they  will show "Remote

down" when having data/signal problems and they both look  normal.  Not sure

where to go with this if swapping host FSU doesn't do  it.  Thanks.  Neil

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Valued Contributor
Valued Contributor

Re: What does a steady green "RDN" indicator light mean?

It could be just a bad DTE cable as well. All the LEDs show is that there is no longer any data transmitted to or received from the end equipment.

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Re: What does a steady green "RDN" indicator light mean?

Patrick: Got it. I will try new cables. Thank you! Neil

In a message dated 6/20/2014 3:52:49 P.M. Eastern Daylight Time,

adtran@adtran.hosted.jivesoftware.com writes:

ADTRAN Support Community (https://supportforums.adtran.com/index.jspa)

What does a steady green "RDN" indicator light mean?

created by patrick (https://supportforums.adtran.com/people/patrick) in

Express Series - View the full discussion (https

://supportforums.adtran.com/message/14910#14910)

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New Contributor

Re: What does a steady green "RDN" indicator light mean?

Patrick:  Tried cables at remote as well as swapping muxes at remote and still had same symptom.  Then I tried swapping out adtran fsu at host.  So far that seems to have fixed it, but since our remote site is not staffed continuously this time of year I don't know if problem is resolved permanently.  I will keep you posted.  Thank you for the help!  Neil

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New Contributor

Re: What does a steady green "RDN" indicator light mean?

Patrick:  Sorry for the delayed update.  All has been resolved with steady green "RDN" light displayed on the remote side FSU.  Turns out the problem was a bad DSU at the Host side that I must have missied on my first diagnostic test there.  All is well.  Thank you so much for your assistance!   Neil