An ANS 500/132 may be upgraded to an ANS 500/200 by installing the 200 MHz processor accessory card. It is possible to upgrade an ANS 500 to an ANS 700 or to downgrade an ANS 700 to an ANS 500 simply by exchanging the power back panel and PSU(s), but it is necessary to completely disassemble the base of the ANS in order to accomplish such an upgrade or downgrade. An ANS 700 has but one input power connection, even though it has dual, independent PSUs. However, an ANS 700 may be easily converted into a dual primary power configuration (independent primary power, possibly, and desirably, from different power panels, one possibly backed up by an uninterruptible power supply) by removing the IEC input power connector and physically and electrically connecting two input power cordsets, one to each of the redundant PSUs. However, this modification probably invalidates the machine's UL Listing. Nevertheless, such a modification would implement a true N+1 redundancy configuration.