----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, May 02, 2002 10:51 AM
Subject: [plug] connection speed?
> X-Urios College, Butuan City, Caraga, Philippines: My.Urios
>
> what is E1R2?
E1 is a channelized digital line operates at 2048 kbps and is made up of 32
x 64 kbps channels.. R2 is an ITU signaling for E1 channelized line
signaling...
allow me to explain how 56k works..
here is the current topology for standard 33.6k connection
computer
^
|
(digital signal)
|
v
modem
^
|
(analog signal)
|
v
PSTN DAC/ADC (public switched telephone system digital-analog
coverter/analog-digital re-converter)
^
|
(digital signal)
|
v
PSTN DAC/ADC (public switched telephone system digital-analog
coverter/analog-digital re-converter)
^
|
(analog signal)
|
v
isp modem
^
|
v
internet
for 56k topology
computer
^
|
(digital signal)
|
v
modem
^
|
(analog signal)
|
v
PSTN DAC/ADC (public switched telephone system digital-analog
coverter/analog-digital re-converter)
^
|
|
(digital signal) E1/R2 line
|
|
v
isp modem
^
|
v
internet
for 56k connection, there is no DAC/ADC conversion at the isp side which can
boost the downstream upto 56kbps but still the upstream of a client is
33.6kbps..
the main reason why you cant achieve 56kbps connection for a 56k access is
that the FCC has a rule that limits its signal strength, which in turn
limits modem speeds to 53kbps only
if you cant still get this 53kbps bandwidth eventhough your isp is using an
e1/r2 line (or equivalent like in USA/Japan is using T1), the following
reasons are:
1. dirty line or noisy line
2. if you have a clean line but drop to 33.6kbps or below, there is an
analog repeater within your vicinity which knock down the achievable speeb
back to 33.6kbps.
fooler.
_
Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph
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