NCE produced the Dual relay to allow both the Switch-it and the Switch 8 to operate as a digital switch using the Dual relay.
The reason is solid-state transistor switch on the decoders can only handle about 40 ma, which is more than enough for a typical; Tortoise motor but is limited to that. The Dual Relay was created to handle up to 2 amps to allow the decoder to switch a relay. To achieve this, the relay coils had to have high resistance to limit the current within both decoder specifications.
There is an error in the nomenclature printed on the decoders. It's all back to front, and if wired as shown, it will not operate, or the wrong outputs will operate.
I have created a correct corrected image that will operate as specified when wired as shown will operate to specification..