A device arrangement may include an electronic device at least partially enclosed in a device casing. In these methods, a device is engaged in data communications with a second device and receives a conflicting communication demand requiring action on one or more channels other than the data-communication channel. The light which has irradiated the gap and has not been interrupted but diffracted by the gap is detected on a light-receiving sensor to measure the length of the gap. The tuples are recorded in a quantile-digest data structure. The current source further includes a second circuit and a third circuit. Some caps can create a seal with the medical connectors to prevent antiseptic from entering a fluid paths defined by a connector.