Not all phone lines (loops) are alike. There are three major ways that loops are provisioned:

Loop Provisioning Summary

ADSL can only run over the copper portion of a loop. Two DSL modems are required: one at the customer home and one where the copper portion of the loop terminates. Since many customer loops terminate in a common location, the second DSL modem is usually part of a large rack of modems called a DSLAM (DSL Access Multiplexor).

ADSL over straight copper loops requires:

• Home must be < 18,000ft from the central office
• Unloaded pair (no load coils)
• DSLAM installed in central office

ADSL over Universal SLC requires:

• Home must be < 18,000ft from the USLC
• Unloaded pair (no load coils)
• DSLAM installed in remote terminal

ADSL over Integrated DLC requires:

• Home must be < 18,000ft from the IDLC
• Unloaded pair (no load coils)
• DSLAM installed in remote terminal

IDSL requires:

• ISDN availability (approx. 90%+ homes qualify)
• Straight copper or Universal SLC loops ONLY
• Home must be < 18,000 ft from central office (36,000ft w/repeater)
• Unloaded pair (no load coils)
• IDSL capable DSLAM intalled in central office

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