bscribers. Care Phase SW Upgrades With the onset of new business models software sales are becoming some of the major business mod- els, where feature based software modules are kept separate from the basic operating software module. Software upgrades are done by putting together totally new software packages or by installing some new change notes compiled together as 'change deliveries'. It brings in new functionalities, improved perfor- mance figures, higher success rates, new or improved additional features, improved network stability and reliability. All software upgrades are pretested in the network operator's test network and all features and functionalities are tested thoroughly to their last details before being installed on a live network. Before any software upgrade is done, there is always a team from both sides, i.e. the vendor and the operator, the former taking responsibility for doing the complete software upgrade and the latter taking the part of overall supervision and doing the final checking and testing before signing off the activity sheet with normal acceptance. Most live upgrade activities are done in two shifts. In the first one the upgrade engineer either goes to the site physically or takes charge of the equipment remotely from the operation and maintenance centre. Before beginning at a software level, the latest technical notes are checked for any hardware modifications or additions. In typical cases memory blocks are added or replaced with bigger ones, new plug-in unit versions are installed or the interchangeability codes are updated to the latest ones. Firstly, the alarms are checked to ascertain the equipment's stability and to find out whether any major alarms need to be taken care of. Then the current software package is backed up in the hard disk as well as in a DAT (digital audio tape) or magnetic optical disk for future reference or fallback, in case the upgrade fails for any human or technical reason. Then precheck macro is run to extract the running data of the equipment, whic