Abstract: An ambulatory physiological computer recorder that includes multiple selective plug and play signal input conditioners, a microprocessor system with operating and analyzing software and a removable memory module for data storage. The removable memory module may consist of any non-volatile memory such as IC memory, magnetic memory, optical memory or magneto-optical memory. The removable memory module used in the recorder excludes operating software; the purpose of the removable memory module in the recorder is only to receive and store acquired data. The recorder uses an alpha-numeric LCD display with control buttons for user interface to enter patient ID and recorder functional perimeters. Both operational and selective analysis software is resident in the microprocessor EEPROM memory. Software is installed in the recorder by transfer from an external source via standard serial or parallel links with applicable connectors, or by a plug-in EEPROM.