How does an ISDN connection work?

People attempting to establish rural service via a Wireless ISP, ISDN, or T-1 will run into an additional cost issue, where the physical connection (or local loop) is considered separate from the actual Internet service provided from a Point of Presence (POP). In the US the loop alone may cost $1200 per month, and the 1.5 megabit per second business-class Internet service (with a fixed IP address and a subnet) may cost an additional $1000 per month. Attempting to reduce monthly costs by establishing your own non-profit Wi-Fi network and sharing the T-1 connection costs has an additional pitfall: your service provider may want to charge you an additional "ISP reseller's fee" of $800 per month.