Quote:
Originally Posted by JimsShed
then he asked how many spare phone sockets I have in the house. I said 3 but nothing plugged into them. He told me to get them physically disconnected except for the socket with the NBN router. So I did and I immediately got 23/3 speeds!
Apparently the sockets cause the signal to bounce around and degrade.
Jim
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Hi Jim,
I gather the spare phone sockets were connected to the same twisted
pair that runs out to the street? That is, they were on the same line
that the NBN boxes use to connect to the external network?
If that were the case and the installer left the existing spare phone
sockets still connected to the same line that goes out to the network,
then that sounds negligent.
By way of background the signals coming down the twisted pair outside
in the street to your house will have relatively fast "rise times".
The speed of light is disappointingly slow and travels only about 1 foot
(300mm) in a nanosecond (one billionth of a second).
When a signal travels down a wire, it travels at a fraction of the speed
of light.
When the signal's rise times become faster than the distance it travels
down a pair of wires, then you are in the domain of what engineers
refer to as transmission line theory.
The wires themselves have what is referred to as a characteristic
impedance (an effect of resistance, inductance and capacitance) and
just like when you tie one end of a rope onto a brick wall and flick
the other end to send a pulse wave down it, when the pulse hits the
end tied to the brick wall it will bounce back.
So engineers have to terminate the line with an impedance that matches
the characteristic impedance of the line itself to avoid reflections and
the signal thus interfering with itself. The NBN box would have this
termination.
But add unterminated branches to the transmission line such as unused
phone sockets and you could have multiple reflections which would
degrade your network performance.
Any additional phone lines should have just come from the appropriate
sockets on your modem.
If this is what happened in your case, then it begs the question how many
other FTTN and FTTC network connections have been improperly
installed around the continent.
