When you apply for a new telephone or internet connection, your service provider needs to connect the wiring from the telephone exchange to the Main Distribution Frame (MDF) in your building or apartment complex. The connection on the incoming side or the MDF is called the ‘A’ side. The A side of the MDF is the property of the service provider or ISP.
Put another way, the MDF is the connection point or box that all the incoming phone and internet lines from the street connect to. The other side of the MDF is generally called the B side. and this is where the wiring from the individual homes in the unit complex are jumpered or connected to the telephone or internet line and number they have been allocated. After your service provider has connected to the A side of the MDF they will usually tag the line to identify it for the technician who will connect it to your line on the B side of the MDF. This process is called jumpering. A jumper wire is run between the service providers A side connection point that brings your number into the building and the B side that is connected to your unit.
For larger apartment complexes and commercial buildings with numerous floors, there often intermediary Distribution Frames (IDPs) and sometimes a Final Distribution Point (FDP) that services may need to be jumpered through before service reaches your unit.
This is a common question we are asked. In most cases, when your ISP technician connects your new internet service to the MDF, they will install it to a new point on the frame, instead of the existing point where the previous tenant had their internet connection. This is common practice and there a couple of reasons why they do this;