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Seer's avatar
Seer
New Contributor

T3 Timeouts

Well here we go again T3 timeouts and 4 technicians later all contractors.  We had one out yesterday who found the cable from the green tower on my lawn to the box on the side of the house and he replaced it.  I rebooted the modem and the new ac router and it was good till 0532 this morning when lo and behold there's a T3 timeout and since that time I have had several more this morning.  Now this is getting quite old hearing "oh we need to send a tech out again"  I am a field service tech as well for a computer system company and I would like to have Cox check the amplifier on their end as well. 

The tech who came out called a supervisor and he went over the readings as well.  I am a patient person but my patience is wearing thin at this point.

My readings as of 0831 27 Jan 2017

Channel ID

46  43  44  45 
Frequency 927000000 Hz  909000000 Hz  915000000 Hz  921000000 Hz 
Signal to Noise Ratio 37 dB  37 dB  37 dB  37 dB 
Downstream Modulation QAM256  QAM256  QAM256  QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
5 dBmV   6 dBmV   6 dBmV   6 dBmV  
Upstream Bonding Channel Value
Channel ID 4  1  2  3 
Frequency 36300000 Hz  18400000 Hz  23300000 Hz  29800000 Hz 
Ranging Service ID 501  501  501  501 
Symbol Rate 5.120 Msym/sec  2.560 Msym/sec  5.120 Msym/sec  5.120 Msym/sec 
Power Level 38 dBmV  36 dBmV  35 dBmV  39 dBmV 
Upstream Modulation [3] 16QAM
[3] 64QAM
 		 [3] QPSK
[2] 16QAM
[3] 64QAM
 		 [3] 16QAM
[3] 64QAM
 		 [3] 16QAM
[3] 64QAM
 
Ranging Status Success  Success  Success  Success 
Signal Stats (Codewords)Bonding Channel Value
Channel ID 46  43  44  45 
Total Unerrored Codewords 2524899367  2524899281  2524899371  2524899285 
Total Correctable Codewords 11  20  9  11 
Total Uncorrectable Codewords 661  744  664  751 

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  • ChrisL's avatar
    ChrisL
    Former Moderator
    @Seer

    If there is anything on the lines that needs to be checked our field service technicians would be the one to put in a request with our maintenance team to investigate. I'm also seeing indications of a possible power issue at the modem. Have any of the technicians tried testing with a different modem to see if that helps? It may also be worth trying to connect the modem to a different power source and see if there is any change.

  • Seer's avatar
    Seer
    New Contributor

    They have not tried with a different modem, I will try a different plug and see if that helps.  I am beginning to wonder if it may be the modem.

  • ChrisL's avatar
    ChrisL
    Former Moderator
    @Seer

    The modem is definitely a possibility, testing with a different modem would help to try and isolate that further.

  • Seer's avatar
    Seer
    New Contributor

    I found this on speedtest.net

    Apparently, from reading many entries on several user forums, it seems to be exceedingly touchy about power levels, the specs for which are much tighter than for the SB5101. Which touchiness has created, and continues to create, a BIG problem for users, at least some of them, on the Comcast network. Motorola blames the problem on Comcast.
    -- However, users on other carrier networks experience the same problem.
    -- Motorola blames it on the DOCSIS 3.0 specs.
    -- Other DOCSIS 3.0 cable modems do NOT have a problem with excessive power level sensitivity.

  • cpljp's avatar
    cpljp
    Contributor

    Doubt the power levels are causing the issue. That range is well within what the tuner is designed to handle. Unless the tuner is also getting hit by a high amount of total RF power from the rest of the frequencies riding on the coax line...i.e. 75 to 800 MHz of spectrum not being utilized by the modem. But if this was the case, we would see whats called "reverse tilt" which would impact your modem by having a lower SNR than the 37dB you're seeing right now. 

    FWIW, you will see a T3 timeout here and there. Its part of the many things that come with using this technology. But too many is when it becomes an issue. I know you don't want another tech out, but I'd recommend having another service call and ask that tech (if he's not a contractor" to call a line tech and see if the line tech sees any noise in the node. 

    Unfortunately modem manufacturers will always blame the cable company's network for any issues. Half the time they are right, and the other half they don't know what they are talking about.

  • Becky's avatar
    Becky
    Moderator
    Hi Seer,

    Is the modem plugged directly into a wall outlet, or does it plug into a power strip or surge protector?


  • Seer's avatar
    Seer
    New Contributor

    Replaced the modem with a Zoom 5370 got a couple unicast errors which I can live with I have also noticed the correctable and uncorrectable codewords have all but disappeared from the modem as well.  Now can these code words cause issues?  I am going to monitor this and see what happens