Abstract: An ambulatory physiological monitor includes a high capacity, plug connectable magnetic disk cartridge for storing physiological data and analysis software. The disk cartridge is easily removable from the monitor and is connectable to a remote computer for analysis of the physiological data using the analysis software stored in the disk cartridge. The ambulatory physiological monitor may include a wireless data modem for communicating with a remote computer system as to the patient's condition through a cellular telephone system. Selected portions of the physiological data or results of analysis of the physiological data may be transmitted to the remote computer system. The monitor may operate in a server mode in which it is controlled by the remote computer system. Updates to the analysis software and remote commands may be sent from the remote computer system to the monitor.