Methods for configuring, maintaining connectivity in and utilizing an ATM network. A first switching device is coupled to the first input and a second switching device is coupled to the second input, with control circuitry configured for selective switching between a reset mode and a compare mode. In the preferred embodiment MB1 and MB2 are coupled to the control terminals of M1 and M2 for establishing a bias voltage at the control terminals of M1 and M2. Both the amplitude data and the variable density log data are captured in memory downhole by the use of a time amplitude matrix which stores a limited number of data points for producing a cement bond log at the well surface. The first zone vacuum retention force to vacuum ports formed in the pockets to retain the can bodies within the pockets.