[VoIP] Cable questions

[Mark Rudholm]

Jayson Smith wrote:
> Hi,
> After this eventful weekend of lost DSL, dead DSL jacks, resurrected DSL
> jacks (we now have DSL and the jack wasn't replaced), phone line static,
> some DSL failures after that, etc. we are getting disgusted with Bell South.
> We've found we can actually save some money by switching to cable for
> broadband and phone service. I have a few questions.
> On the phone side of things, how does this work from a technical standpoint?
> Is dialtone being provided by the box they put at the house, or does it
> actually connect digitally to a real switch somewhere, which provides
> dialtone, ring, busy, etc? Also, if the power goes out, what happens? Do you

Dialtone is provided by the box at your house.  The ones my cable
company uses have internal batteries that are good for eight hours.
They don't compete for bandwidth with yours (or your neighbors')
Internet service.  They're on a different IP network than the
cable modems, just as the set-top boxes are.  Granted, this is the
case for my cable company, YMMV.

> get a little battery backup, then dead phones until the power comes back? Is
> it possible for a customer to hook the phone converter box up to a UPS, or
> is this strictly illegal/impossible/etc? I assume sound quality should be
> comparable to ULAW Voip service.

Yes, it should be.

>      About Internet, what kinds of speeds can I realistically expect? I
> think our DSL is now 1.5 Mbit down, and a lot less than that up. I don't
> know what cable is even claiming. Also, does the cable modem typically have
> to be hooked up directly to a PC for initial
> installation/activation/whatever, then hooked up to a router, or can it
> usually all be done from the router?

This is going to vary depending on what your cable co offers in your
area.  Where I live, the best I can get is 10Mb down, 1Mb up.  The
1Mb up is very consistent, but the download speed varies from 10.5Mb
to about 2Mb depending on the time of day.  The best DSL speed I
could get (limited by my loop length) was 2Mb down, and 368kbps up.
Here's a graph of my cable modem's download speed for this month:
http://brainflux.net/~mark/netspeed.html  You'll notice that in
the early morning hours speeds are consistently good, but then
during the evening they vary quite a lot.  Jitter and latency are
generally pretty good, though.  That dip down below 1Mb earlier
this evening was from me saturating my upload bandwidth (copying
a few hundred MB to my colocated server).

Generally installation is very simple, the tech will bring out the
modem, ask you for a computer to plug it into for installation, but
then you can just plug it into anything you want when they're done,
including a home NAT router.  Some cable companies will even provide
a modem that has the router and wireless AP built in.

There really is no clear winner when comparing advantages and
disadvantages of cable vs. DSL in my opinion.  So what it's going
to come down to is the skill/quality of the vendor more than the
technology they're using.  Either can be good, and either can be
really poor.

>      One thing I'm dreading is changing E-mail addresses with everybody I
> know, do business with, etc. Oh well. Thanks for any info.

You might consider going to a yahoo.com or gmail.com email address
so that your email address is not tied to your ISP.

-Mark