Hardware Reference
In-Depth Information
Modems that support V.92 typically also support the V.44 data-compression standard.
V.44, which replaces V.42bis, provides for compression of data at rates up to 6:1—that's
more than 25% better than V.42bis. This enables V.92/V.44 modems to download pages
significantly faster than V.90/V.42bis modems can at the same connection speed.
ISP interest in this standard has been tepid, mainly because it requires upgrading expens-
ive equipment at a time when the market has been shifting to broadband.
According to the V.92 News & Updates page at Richard Gamberg's Modemsite
( www.modemsite.com/56k/v92.asp ) ,even after upgrading tosupportV.92/V.44,some ex-
isting terminal hardware is incapable of working with the desirable PCM Upstream fea-
ture. Additionally, many major modem vendors have produced so-called “V.92” modems
that don't support major V.92 features. Check user reviews available at the Modemsite
website and others to determine the level of feature support in a particular V.92 modem
model.
Internet Connection Security
Virtually all forms of Internet connections use some type of external modem, which acts
asabridgebetweentheInternetandyourPCand/oryourlocalnetwork.Many,ifnotmost,
of these modems are just modems, and they do not include other functionality such as a
routeroraswitch.Somemodemsincludeabuilt-inrouter,andothersincludebotharouter
and a switch. There is an important distinction between them, and you need to know the
ramifications before you use them.
The most important thing you can do for security when using a broadband Internet con-
nection is to ensure that you are connected though a router, which acts as a gateway with
a hardware firewall between your local network and the Internet. A router includes a
DHCP (Dynamic Host Configuration Protocol) server, which allows it to automatically
assignprivateIP(InternetProtocol)addressestosystemsonyournetwork.Then,oncethe
addresses are assigned, the router uses NAT (Network Address Translation) to translate
packetsmovingbetweentheprivateIPaddressesonyournetworkandthepubliclyvisible
IP address assigned to the router itself. Using NAT, only the router is publicly visible on
the Internet; all of the systems behind it are effectively hidden. This provides a hardware
firewall to protect the PCs on your network.
If your modem includes multiple Ethernet ports for connecting PCs, most likely it has
both a router and a switch built in. In that case, you can connect PCs to the modem/router
safely, and the built-in router will protect your systems. If your modem has only a single
port,thatmeansitdefinitelydoesn'tincludeaswitch,andmayormaynotincludearouter.
If it does include a router, and you only want to connect a single PC, you can connect it
directly to the Ethernet port. However, if it doesn't include a router, you need to connect
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