The 66 block is where dial tone from the Dmarc comes in. I can't think of the actual name of the block, but it is not split. The horizontal pins on each row are bridged.
So both Blue and Orange are feeding 439-XXX0
Brown and Green are feeding 439-XXX1
Unsure as to why it was done like that.
The white cable with the 8p8c connector is feeding to two surface mount blocks for the alarm system. The way to blocks are wired, there is no line seizure for the security and fire systems.
