Modem won't sync or loses sync

Modem won't sync or loses sync
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Subject Author Date
Modem won't sync or loses sync tabby55 06-17-2006
Posted by on June 17, 2006, 2:18 pm
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I have had cable internet service from Cox for 3 years in this house.
All of the sudden my modem will either not sync or lose sync after a
while.

Cox said that if they come out and it is my fault they will charge me
$49.

So I tried an experiment. I unhooked the modem and took it to another
room and connected it. It synched immediately. The weird thing was
that when I took it back to the computer and connected it. It also
synched right up. I have tried this for three days now and it never
fails to work. Take the modem in the other room and hook it to the
cable outlet. Power it on, let it sync, unconnect it and take it back
to the computer. I am then good for about 4-6 hours.

What could be going on and why does synching in the other room allow
the modem to sync when I bring it back to the computer.

It is not the cable used to connect the modem to the wall outlet. I
have tried different permutations of cables and outlets and it makes no
difference. Also, neither of these outlets have a splitter. (No
splitters in the house, in the wall? who knows?)


Posted by $Bill on June 17, 2006, 2:54 pm
tabby55@gmail.com wrote:

> I have had cable internet service from Cox for 3 years in this house.
> All of the sudden my modem will either not sync or lose sync after a
> while.
>
> Cox said that if they come out and it is my fault they will charge me
> $49.
>
> So I tried an experiment. I unhooked the modem and took it to another
> room and connected it. It synched immediately. The weird thing was
> that when I took it back to the computer and connected it. It also
> synched right up. I have tried this for three days now and it never
> fails to work. Take the modem in the other room and hook it to the
> cable outlet. Power it on, let it sync, unconnect it and take it back
> to the computer. I am then good for about 4-6 hours.
>
> What could be going on and why does synching in the other room allow
> the modem to sync when I bring it back to the computer.
>
> It is not the cable used to connect the modem to the wall outlet. I
> have tried different permutations of cables and outlets and it makes no
> difference. Also, neither of these outlets have a splitter. (No
> splitters in the house, in the wall? who knows?)

Please supply your modem make/model and your connection settings/power
levels from the modem's status pages. Also a diagram of your cabling
including cable type (RG6/RG59) and splitter models would help. If
your transmit levels are high, you may have a cabling problem exacerbated
by that 100+° AZ heat or maybe your modem is overheating.



Posted by Culican on June 17, 2006, 3:06 pm
$Bill wrote:
> tabby55@gmail.com wrote:
>
>> I have had cable internet service from Cox for 3 years in this house.
>> All of the sudden my modem will either not sync or lose sync after a
>> while.
>>
>> Cox said that if they come out and it is my fault they will charge me
>> $49.
>>
>> So I tried an experiment. I unhooked the modem and took it to another
>> room and connected it. It synched immediately. The weird thing was
>> that when I took it back to the computer and connected it. It also
>> synched right up. I have tried this for three days now and it never
>> fails to work. Take the modem in the other room and hook it to the
>> cable outlet. Power it on, let it sync, unconnect it and take it back
>> to the computer. I am then good for about 4-6 hours.
>>
>> What could be going on and why does synching in the other room allow
>> the modem to sync when I bring it back to the computer.
>>
>> It is not the cable used to connect the modem to the wall outlet. I
>> have tried different permutations of cables and outlets and it makes no
>> difference. Also, neither of these outlets have a splitter. (No
>> splitters in the house, in the wall? who knows?)
>
> Please supply your modem make/model and your connection settings/power
> levels from the modem's status pages. Also a diagram of your cabling
> including cable type (RG6/RG59) and splitter models would help. If
> your transmit levels are high, you may have a cabling problem exacerbated
> by that 100+° AZ heat or maybe your modem is overheating.
>
>
x Power        52.5        dBmV
Rx Power        -12.2        dBmV
Downstream SNR        37.2        dB
Tx Frequency        19600000        Hz
Rx Frequency        579000000        Hz

It is a Terayon TJ715x

Dr. Modem has examined your modem.
Dr. Modem's Diagnosis:
# The modem is fully operational.
# Upstream Power level is high (52.5) and Downstream Power level is low
(-12.3)

I have no splitters in the house that I know of. However, the outlet I
use in the bedroom for the cable modem is on the other side of the wall
from the living room, where the TV is connected. None of the other
outlets share a wall (they are all on exterior walls) Perhaps there is
a splitter in the wall?

Here is the event log:
2006/06/12 18:37:37        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:37:37        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 4.
2006/06/12 18:39:40        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:39:40        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:39:40        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 1.
2006/06/12 18:40:59        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:40:59        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:40:59        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 4.
2006/06/12 18:42:00        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:42:00        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:42:00        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 3.
2006/06/12 18:43:16        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:43:16        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:43:16        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 2.
2006/06/12 18:44:56        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:44:56        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:44:56        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 1.
2006/06/12 18:46:17        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:46:17        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:46:17        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 3.
2006/06/12 18:47:34        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:47:34        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:47:34        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 2.
2006/06/12 18:49:00        82000200        16        Critical        No Ranging Response received -
T3 time-out.
2006/06/12 18:49:00        82000300        1        Critical        Ranging Request Retries exhausted
2006/06/12 18:49:00        85000200        1        Critical        UCD invalid or channel unusable
- T3 timeout: Giving up on UCD 4.
1970/01/01 00:00:20        68000100        9        Critical        DHCP FAILED - Discover sent, no
offer received - DHCP init timeout!
1970/01/01 00:00:03        2242905932        1        Notice        SNMP Poll - Eth Link Up.
1970/01/01 00:00:14        68000100        1        Critical        DHCP FAILED - Discover sent, no
offer received - DHCP init timeout!
2006/06/17 10:45:24        2242905917        1        Notice        SNMP Poll - Mac Link Up.
2006/06/17 10:45:24        2242905786        1        Notice        SNMP Poll - DS Link Up.
2006/06/17 10:45:24        2242905803        1        Notice        SNMP Poll - US Link Up.
2006/06/17 10:45:24        2242905723        1        Notice        SNMP_AGENT_COLD_START

Posted by $Bill on June 17, 2006, 10:00 pm
Culican wrote:

> Tx Power        52.5        dBmV
> Rx Power        -12.2        dBmV
> Downstream SNR        37.2        dB
> Tx Frequency        19600000        Hz
> Rx Frequency        579000000        Hz
>
> It is a Terayon TJ715x

Your TX is on the high side - higher than I'd like and the RX is low.
Either the CableCo needs to kick up the signal or you need to upgrade
your cable/connections.

I have a TJ715 - here's my current numbers which are so-so :

RF Parameters
        Parameter        Value                Units
        Tx Power        48.2                dBmV
        Rx Power        -2.8                dBmV
        Downstream SNR        32.3                dB
        Downstream MER        31.5                dB
        Tx Frequency        33000000        Hz
        Rx Frequency        705000000        Hz

> I have no splitters in the house that I know of. However, the outlet I
> use in the bedroom for the cable modem is on the other side of the wall
> from the living room, where the TV is connected. None of the other
> outlets share a wall (they are all on exterior walls) Perhaps there is
> a splitter in the wall?

1) Take a look at your interior cable and see what is written on it
(RG6/RG58/RG59). Look inside your wall plates and see what sort of
devices are there.

2) If you have a TV and a modem, there must be a splitter somewhere unless
you have two lines coming in from the pole. Trace back to the entry
into the house and see what's there.

Normally you would have a grounding block and a splitter (presumably 1 leg
for each cable run). You would want the modem on it's own leg (you can
split the TVs further down the line if necessary, but not the modem).

Check that all your connections are tight and corrosion free - I'd replace
RG58/59 if it goes to your modem with RG6 - it's probably OK for your TVs.

Here's an example from my house (haven't gotten around to replacing RG59
to the TVs yet, but they work OK) - you should make one of these up for
your house :

/-- Grounding block pass thru connector (grounded to electrical box)
|
| RG6 Terayon Netgear PC1 PC2
| /------> TJ715 Modem ----> RP614 Rtr ------|---|---|---|
V /
--------->X----->X <-- Signal Vision SV-4G digital 4-way splitter
U/G cable \ (5-1000Mhz) 7dB/port
         |
| RG59
|-----------------> to Family Room (below) -->
| RG59
|-----------------> BR1 TV
| RG59
\-----------------> BR2/3 TV (terminated)

RG59
/-----------------> TV1
Family Room /
-------------X <--- Pico Macom Tru Spec TSV-8SB 1-8 splitter -10.7 dB/port
\
| RG59
|-----------------> TV2
| RG59
|-----------------> TV3
| RG59
|-----------------> VCR1
| RG59
|-----------------> VCR2
| RG59
|-----------------> VCR3
| RG59
|-----------------> PC1
| RG59
\-----------------> (terminated)





Posted by Culican on June 17, 2006, 10:20 pm
$Bill wrote:

> 2) If you have a TV and a modem, there must be a splitter somewhere unless
> you have two lines coming in from the pole. Trace back to the entry
> into the house and see what's there.

I watched the tech when he installed the whole set up 3 years ago. I
seem to recall that one cable comes underground from across the street
(one of those cylindrical Cox boxes there). At my box on the outside
wall there was a splitter and 4 cables leading into the house, one for
each outlet.

I will definitely check all of the items you said.

Thanks

I am kind of disappointed in Cox. When I called support the guy had no
clue about my modem; said that since it was not synched he could not
check anything. Didn't tell my about logging into it and getting the
numbers, etc. I found all that out on Google (as well as the password
to get into the modem.)



BTW: My modem was out of sync for several hours. I wanted to get online
so I was going to move it to the other room where it works. I screwed
in a 3 foot piece of cable into the wall outlet, went back to get the
modem and ...yes you guessed it, it was synched. Why would a three foot
stub of cable screwed into another outlet allow the modem to synch? I
checked the numbers and they were better than the ones I previously
posted but still too high up and too low down.

Thanks again.

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