# Motorola SB5100 Cable modem Problems



## Telios (Dec 4, 2007)

I thought I'd post this here, maybe some one can help.
I own the above mentioned cable modem and am experiencing problems
with intermintent dropping of the (ethernet) connection between my PC and the modem. I have swapped cables three times now. It seems like it is
holding the connection, but will see. The modem does not loose the connection to the cable internet, only to my PC, it seems. I was originally using it through my NETGEAR router with same problems. Before that I had a SMC wireless router set up. I kept thinking it's the cable company (Rogers in Ontario, Canada), but it turns out that it is a local problem.
Has anyone else had problems like this, with this model of modem?
Any input appreciated.

My comp is a XP home with 1Gig of RAM and 200Gig HDD. The ethernet card is integrated. CPU is Intel P4 3.1gHz HT.


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## johnwill (Sep 26, 2002)

The Ethernet port on the modem could be bad, hard to say. Since you have tried more than one router and cable, it seems you're down to the modem.


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## Telios (Dec 4, 2007)

johnwill said:


> The Ethernet port on the modem could be bad, hard to say. Since you have tried more than one router and cable, it seems you're down to the modem.


Well, last night when I started this thread I had the modem connected directly to the computer via ethernet cable. This morning after booting
up internet still works. Maybe one of the other cables was faulty.
I don't have a network cable tester so I have no way to test for bad cables.
The manual for the modem says to use a straight through cable for Modem to Comp connections and a crossover one for modem to router connection.
How do I know which is which?

:4-dontkno


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## johnwill (Sep 26, 2002)

The manual appears to be faulty. The router WAN port is the same connections as a standard NIC, and is normally connected using a plain patch cable.

What's the exact make/model of that modem, and do you have a link to the manual?


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## Telios (Dec 4, 2007)

johnwill said:


> The manual appears to be faulty. The router WAN port is the same connections as a standard NIC, and is normally connected using a plain patch cable.
> 
> What's the exact make/model of that modem, and do you have a link to the manual?


The modem is the Motorola SB5100.
The manual is here:
http://search.motorola.com/query.html?qp=site:broadband.motorola.com&qt=SB5100&x=19&y=10

Directly from Motorola.


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## johnwill (Sep 26, 2002)

I just realized the model of the modem was in the title of the thread. :embarased

I think it's just defective, you've eliminated everything else. FWIW, I had two cable modems die here before I went with Verizon FiOS, it does happen.


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