Solution(s)
Anything that adds noise to the telephone
line or causes an analog-to-digital conversion between your Internet
connection and your modem lessens the transmission's performance.
For 56K to work, you can have at most one analog-to-digital
conversion between your home or office and the Internet service provider. If
there's more than one, you can't use 56K, and your connection will be limited
to V.34 speeds (a maximum of 33.6K).
The FCC says "no more than 53 kbps"
Though your
modem says it's "56k," you won't get throughput that fast, thanks to a speed
limit set by the FCC (Federal Communications Commission). The reason for that
regulation? Sending a signal down a telephone wire requires electrical power.
But the more power you apply, the greater the chance of a problem called
crosstalk. You've encountered this annoyance if you've ever heard other
people's conversation during a phone call. To help prevent crosstalk, the FCC
limits the amount of power that phone companies can use to send signals over
the network. And this cap on signal strength limits data throughput to a
maximum of 53 kbps, regardless of what your modem can actually deliver. The
FCC is currently reviewing this ruling and may overturn it later this year to
enable true 56-kbps modem connections.
Office PBX systems
If you have to dial 9 to get
an outside line, your office uses a digital PBX telephone system, which means
you also won't be able to achieve 56k rates. A PBX system incorporates a codec
that performs an analog-to-digital conversion so that your calls can be stored
digitally on magnetic media, such as hard disks. Though this system gives you
some great features, such as employee extensions and call forwarding, it also
limits your 56k calls to a maximum throughput of about 35 kbps.
Noisy analog lines
Digital lines usually don't
suffer from noise problems, but the analog wires between the phone company's
central office and your home are a different story. If you hear buzzing or
static when you listen through your phone's headset, chances are you won't be
able to achieve optimum modem speed. Caller ID, answering machines, and
cordless phones can add even more noise to your line. To minimize the hum try
disconnecting these types of devices one by one and listening again to
determine which, if any, are the source of the problem. If this doesn't work,
your line noise may be caused by nearby power lines or other environmental or
structural factors.
Central office switch-ups
Connections between
local central-office switches can sometimes be a problem. Old equipment may
require analog termination, resulting in an analog-to-digital conversion as
the call goes through to the next switch. If a local call to your Internet
connection gets routed through these "partially analog" switches, you'll lose
56k capability.
Trouble in the office-to-home commute
There may also be a "pad"
between you and the central office. A pad balances the volume on both ends of
the line when you make a call. If the pad occurs before the signal is
converted to analog, you'll see only a slight degradation in 56k performance.
But if you encounter an analog pad between the central office and your home,
up crops another analog-to-digital conversion to sabotage your 56k connection.
Some local lines also run through an amplifier called a load coil to
boost the signal rates across longer distances. Load coils cause some signal
distortion and will detrimentally affect your modem's 56k throughput potential
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