Hi Seagull, I'm not 100% sure I understand your question. We got the alarm few years back and the broadband last month, so not sure how the alarm is installed - no wires/jacks visible to me. The BT filters came in the post so I plugged them myself (had some problems as I wanted the phone downstairs and the Inet upstairs, and didnt want cables hanging aroudn the house, so the single filter is downstairs next to the phone, double one is upstairs in the office with only broadband cable). Haven't contacted ADT to ask them if that's ok, as I didnt know it may cause a problem, but the alarm hasn't been off since.
Having said that I have to mention we don't switch it on every day as we have a cat, and the technicians never found a suitable solution as to how to keep the cat indoors with the alarm.
Hope this helps! Let me know if it was something else you were asking.