Do I need a new cable modem?

The 1100U is one of Toshiba's first tries at a DOCSIS modem. It's only DOCSIS 1.0 certified, and I don't believe there's anymore support available even to corporate customers. The 1100/1100U occasionally would have issues if either the upstream or downstream channel was changed, as if the modem just couldn't forget the old channel assignment. Couple this with the possibility that the folks writing the new config files for Comcast may not have had any support, and it's believable that the modem is having problems with the speed upgrade.

However, since your problems began "4 or 5 months" ago, it's more likely that there is (also?) a line problem.

The problem is that you own the modem, which in this case cannot automatically be considered good or bad, so the techs won't be able to take the easy way out, and swap modems in an attempt to isolate the problem. The tests done by customer support when you were on the phone may have only been red light/green light type tests, and only valid for that moment in time. Access to some historic logs -- or at least logs from when you were/are having a problem -- would be needed to point one way or the other.

In other words, this is a classic case of when renting the modem beats buying the modem.

If you've already recouped what you spent on the modem, and don't mind spending some (all) of the money you saved in rental fees, you could go out and get a new modem. If the same problems still exist, then it'll be clearer that it there are still problems beyond what could be caused by the config file or the shortcomings of the 1100U. (And I do think that this is what you'll find.)

Are you able to access the cable modem to see the signal levels yourself? Comcast said mine was fine too but the levels were poor when I checked them myself. I read a message from Comcast about a couple modems and the upgrade. But I read it that they just wouldn't get the full speed in some cases.

Thanks for the help out here. I went out and bought a new Motorola SurfBoard 5100 cable modem. Comcast got it registered on their network and although I've only used it about 1 hour so far zero issues. Everything seems to run slightly faster and more reliable but as I said one hour isn't enough time to tell. But I clearly see some improvements. Something tells me the old Toshiba was simply out of date. Thanks again for your help. For those interested in the outcome I'll post again in a few days or so.

Don

@$)#$@&$%^ NO CARRIER

;-)

Well .... I replaced the old Toshiba 1100U with a new Motorola 5100 surfboard cable modem. ALL disconnection issues went away. Plus everything seems to be much faster. This newsgroup was 10 times more helpful than Comcast tech support but then again who really has good tech support anymore? Thanks for your help.

Don

Admit it: you can't beat the support on comp.dcom.modems.cable !-)

Didn't I say that?

Yes indeed you did, and I was facetiously saying what more could you want? :-)

I did the same exact thing u did and I got the same modem as u and ALL my problems were solved