So maybe...
The round box is the phone internal junction box ( like this Bell example
http://upload.wikimedia.org/wikipedia/commons/thumb/... ). This is linked to an external phone junction box through a hole in the wall behind the round box, which is also used by the doorbell wire which appears to go under the round box after originating from the white 3 line junction box by the sunken round pink painted 'cover'.
If so, the 'mains' voltage flows right under the phone's internal junction box and possibly alongside the phone cable from that to the external phone junction box when the bell is rung, by an unsuspecting potential mains voltage induced death candidate.
The RF emmited by the doorbell's coil will be across all frequencies and the higher 'densisty' of data on the download link will be more affected by this.
Other devices will also be affected by the doorbell's coil action and given the state of this section of the OP's home wiring it is no surprise that other effects are manifested in the house.