Hope I'm posting to correct forum.........Helping a friend in trying to establish reason for rediuced (loss of) broadband speed
BT main telephone line, entering via garage terminates in the master bedroom (yes that's correct) in NTE5 box. The main phone is plugged in here. Satellite phones are used throughout the house. A secondary box is located downstairs in his office. These were the only sockets provided when the house was buillt and the routing of the cables is unknown but presumed to be within wall cavities and/or under the floor.
Testing this configuration using a BT Home Hub 3 router from his office, indicates he is achieving around 4,5 mbps download
Now, and additional secondary, dual socket, box has been fitted in the garage directly connected to the customer side of the NTE5 box by approx 3 metre cable (bedroom adjoins the attached garage) . Plugged into this box is an external bell. Again with this in circuit a download speed of 4.5Mbps is achieved. Phones and external bell ring.
Now the rub.....An approx 30 metre cable runs from secondary box in the garage, round the house and into the lounge terminating in another secondary, dual socket box. With this in circuit the download speed drops to approx 2.5mbps.
Remove termination in lounge, still 2.5 Mbps.
Remove termination in garage secondary box, speed back to 4.5 Mbps
Reterminate garage end, drops to 2,5 Mbps
Remove termination in garage secondary box, speed back to 4.5 Mbps and so on
So this 30 metre extinsion cable, terminated or unterminated at lounge end when terminated in the garage, drops the speed by 2 Mbps.
The cable has been renewed. Same issue. All sockets connections has been checked for correct pin usage and wire colour code assigment. No issues there.
Appreciate an explanation on the above scenario, possible causes and what to try next.