DSL bonding

[Jim]

Where I live, I get AT&T for my DSL service.  I've signed up for an 
upgrade from 10 Mbps to 25.  I finally got someone there who would tell 
me why a technician visit is required for the upgrade. They're bonding 2 
pairs to supply the faster speed here.  I've read up online about DSL 
bonding.  I understand that one pair will carry some of the data, and 
the other pair will carry some.  But one thing I didn't find out was 
whether or not anything will change between the wall jack and the 
modem.  Is everything done outside or do they have to come inside?  I 
currently have a 2 conductor cord connecting my modem to the wall jack.  
Will that have to be replaced with a 4 conductor cord?  Do they install 
an extra box outside or inside?  I guess all will be answered on the 
18th when the guy is scheduled to be here.   I'm really curious how this 
works.