Abstract: A test probe for determining the logic state of a digital logic circuit, which probe utilizes threshold detectors to determine the relative voltage level of a test point, and gate circuits to enable various voltage conditions, e.g., a ground, high, low, uncommitted, or a supply voltage, or a random pulse or a pulse train, to be be monitored and the test result indicated on an LED alpha display device. The threshold detectors are selectively settable so that the probe is particularly adapted to test TTL and CMOS circuitry.

Abstract: Provision is made to monitor for vital signs, such as respiratory activity and cardiac activity. The monitoring equipment is mounted by a belt to a person being monitored. Multiple Inductance coils carried by the belt move relative to each other in response to breathing, and the associated mutual inductance changes provide sensory signals to reflect the breathing. Electrical signals indicative of such vital signs are transmitted by radio wave to a central monitor which can monitor the activity of numerous persons. A plurality of such patient units including vital signs sensors and transmitters in combination with a single central monitor may be used to monitor multiple patients. The present invention is useful in monitoring to attempt to prevent sudden infant death syndrome, or crib death, and in intensive care units or cardiac units of hospitals and the like.