A system for monitoring a patient, comprising: a processing system configured to be worn on a patient's body and comprising a processor in electrical communication with a first connector configured to receive a digital data stream from an ECG system; and, a cable comprising the ECG system and a second connector configured to removably connect to the first connector, the ECG system comprising: i) a connecting portion configured to connect to a plurality of electrodes (78a-c) configured to be worn on the patient; ii) a differential amplifier configured to receive electrical signals from each of the plurality of electrodes (78a-c) and process them to generate an analog ECG waveform; wherein the ECG system is comprised by a terminal end of the ECG cable, wherein the cable comprises a housing at the terminal end that comprises at least a portion of the ECG system, characterized in that the ECG system 16 further comprises: iii) an analog-to-digital converter configured to convert the analog ECG waveform into a digital ECG waveform; and iv) a transceiver component configured to transmit a digital data stream representing the digital ECG waveform or information calculated therefrom through the cable (40, 82) and to the processing system, wherein the housing further comprises a motion-detecting sensor configured to generate a digital motion waveform, wherein the cable (40, 82) comprises at least one conductor configured to transmit both a first digital data stream representing the digital ECG waveform or information calculated therefrom, and a second digital data stream representing the digital motion waveform or information calculated therefrom, wherein the first digital data stream comprises a first header portion (210b, 212b) and a first data portion, the first header portion indicating that the first data portion comprises ECG information; wherein the second digital data stream comprises a second header portion (210a, 212a) and a second data portion, the second header portion indicating that the second data portion comprises motion information. a processing system configured to be worn on a patient's body and comprising a processor in electrical communication with a first connector configured to receive a digital data stream from an ECG system; and, a cable comprising the ECG system and a second connector configured to removably connect to the first connector, the ECG system comprising: i) a connecting portion configured to connect to a plurality of electrodes (78a-c) configured to be worn on the patient; ii) a differential amplifier configured to receive electrical signals from each of the plurality of electrodes (78a-c) and process them to generate an analog ECG waveform; wherein the ECG system is comprised by a terminal end of the ECG cable, wherein the cable comprises a housing at the terminal end that comprises at least a portion of the ECG system, characterized in that the ECG system 16 further comprises: iii) an analog-to-digital converter configured to convert the analog ECG waveform into a digital ECG waveform; and iv) a transceiver component configured to transmit a digital data stream representing the digital ECG waveform or information calculated therefrom through the cable (40, 82) and to the processing system, wherein the housing further comprises a motion-detecting sensor configured to generate a digital motion waveform, wherein the cable (40, 82) comprises at least one conductor configured to transmit both a first digital data stream representing the digital ECG waveform or information calculated therefrom, and a second digital data stream representing the digital motion waveform or information calculated therefrom, wherein the first digital data stream comprises a first header portion (210b, 212b) and a first data portion, the first header portion indicating that the first data portion comprises ECG information; wherein the second digital data stream comprises a second header portion (210a, 212a) and a second data portion, the second header portion indicating that the second data portion comprises motion information.