The single-pole double-throw (SPDT) topology is composed of one-pole, two-throw relays. Based on the default position of the pole, one throw is considered normally open (NO) while the other is normally closed (NC). Refer to the NI Product Documentation Center for more information about SPDT topologies.
Note You can resize the SFP window to see more SPDT relays.

Refer to the schematic below for an example of the NI PXI-2566 in the 16-SPDT topology.

Make an SPDT Connection

Click on an individual relay to make an SPDT connection. To connect no5 to com5, for example, simply click on the relay. The pole connects no5 to com5, and the NI-SWITCH SFP makes the appropriate connect/disconnect calls to the driver.