There could be several reasons for slow NBN. For some, there is simple but working solution. This post do not apply to FTTP and to structured cabling topology.
Are you moving to NBN (FTTN and FTTC) in property where cabling was done the telephony way?
Simply change “STAR” topology of your current cabling to direct line. The image shows how most standard property configurations utilizing land line connection.
After switch to NBN (FTTN and FTTC), the structure is used to transmit higher frequency NBN signal. Analog telephony service can be connected directly to phone but no more to existing structure. The loose lines become the real problem as reflection on the not terminated ends degrade line quality and therefore NBN speed.
You should realize that even being less than 300meters form node, Telco technician gives you report which sound “Your connection can carry maximum of 20Mbit/s or less because of low quality copper line”.
Situation can change dramatically when you eliminate loose lines as shown in next picture. Surprisingly you can easily find that your NBN connection is capable 50Mbit or even more without additional change.
Note: It is not difficult at all. It is not dangerous, but it is not legal to manipulate Telco lines. Call certified electrician to make a change.