The Precipice is John Smith's (AKA David Reynolds) key to the J&R/ASA network. It grants the user access to the entire network, evidently regardless of classification. Available information includes troop movements, installation locations, and classified files, such as Project BOXCAR.
Smith evidently created the Precipice as part of his plan against J&R after losing his wife.
Smith used the Precipice in Season Three to located key satellite installations needed for ASA bombing strikes on the East.