The MicroLAN coupler is an essential component to build and control 1-Wire MicroLAN networks with multi-level branching. In contrast to approaches that switch the ground line, the coupler maintains a common ground level for the whole network and keeps the inactive segments powered. This simplifies supplying central or local power for additional circuitry and prevents loss of status of parasitically powered devices. It also avoids disrupting communication caused by the parasitic power supply of 1-Wire devices after activating a branch. The coupler does not contain any user-programmable memory. To label a branch one can connect any 1-Wire memory device to the auxiliary 1-Wire output of the coupler. Both the main and the auxiliary 1-Wire output are supported by a "smart-on" command. This command generates a reset/presence sequence on the selected output before the electronic switch closes the contact to the 1-Wire bus. This way the bus master can apply a ROM function command (optionally followed by a memory function) to the devices on the just activated segment with all other devices in the network 1 of 18