DeTomaso Mailing List: August 99, Message #347

On Thu, 5 Aug 1999, John Darwin wrote:
> Let me briefly review each.
> 
> 1. A phone line is just that. 56kbps speeds. It allows you to use
> current analog modem technology you can buy in any computer store.  In
> my opinion snail slow.

And it's not really that fast... the maximum basic data rate remains close
to 30Kbps.  Those claimed speeds are gained through compression, which can be
horribly ineffective on binary data like all those images on everybody's web
pages, digital audio, movies, etc.  Basically everything but plain text is
difficult to compress effectively.


> 2. ISDN - BRI is a digital telephone line that operates at speeds of
> 128kbps.

One advantage is near zero connect-time.  You dial, and you're digitally
connected in less than a second.  Also very reliable.  My (dedicated nailed)
ISDN line has not gone down even once, for even a second in 8 months of use.


> 3. xDLS There are variants of this. You've probably heard the most about
> ADSL or Asymmetrical Digital Subscriber Line. ADSL is the equivalent of
> a one way T-1 (1.54 Mbps) line to your house. Another way put is, it's
> like having 24 telephone lines going to your house. You can't call out
> on them but others can dial into you. ADSL allows you to send small
> 16kbps command signals to your ISP and they rocket the data back to you
> at almost 1.54Mbps.

But DSL is nothing like a traditional phone line.  Forget about dial tones,
calling numbers, etc... those concepts just don't apply here.

There are many other option with ADSL.  Most companies offer something more
like 128Kbps or 384Kbps out.  The maximum speed (incoming and outgoing
combined) is limited by your distance from the phone company's Central
Office.  Typically you pay more to get more bandwidth.

One downside is that you don't get to choose your ISP - the DSL provider is
your ISP, and that's that... no choice.


> 4. Cable modems allow you to use your cable company's coax line to get
> to the ISP.
[...]
> know of reports that indicate the speeds have not exceeded 384kbps. Not
> very good performance.

Cable modems work great (if you're close to the street - mine kept
overheating because I was too far from the street and the transmitter was
running at full power all the time)... until your neighbors get them too.
It's a shared bus (you and your neighbors are all sharing the same available
bandwidth).  Also bear in mind that a number of the cable modem networks
*prohibit* you from serving any content through your cable modem.  @Home
really screwed me on this, because it wasn't in my service contract when I
signed up, but they later decided to change the rules on the fly, and
enforce it... with no warning to me.  So much for them...

Same downside as DSL: the cable modem provider is the ISP... no choice.

	
> 5. VSAT is DirectTV/DirectPC. If you have a small digital satellite dish
> for TV this service is available to you through DirectTV, Primestar,
> Echostar, etc. You connect your computer to the satellite receiver in
> your house and go. Your computer sends commands to the ISP over your
> telephone line and the data is sent back to you over the satellite
> network. You can achieve speeds of 400kbps. The cost is about $20 per
> month.

This service is actually provided by Hughes.

It is *only* available (for individual use) for Billy Gates PC's.  I will
*never* support any connectivity that is limited to Billy Gates PC's.

Note that you still use a traditional analog modem for your outgoing data.
Also, like a cable modem, you are sharing the available incoming bandwidth
with *all* of the other satellite users.  Turn-around time can be dismal due
to the highly asymetrical route that your outgoing and incoming packets are
taking.

They do provide some innovative services, though, for businesses that need
to "broadcast" digital data to many locations.


> There it is. I hope the forum doesn't mind this post. It doesn't address
> Panteras but it does address our ability to communicate with one another
> about Panteras.

Indeed.  And there's nothing wrong with occasionally helping each other make
educated decisions about our other toys... :-)

-Andy
#3822

72 Pantera - Rocky             91 Miata - Steve                 96 A4Q - Rudolf
80 928 - Phantom               97 Miata - Nadia                84 RZ350 - Sting