Dyno tach signal?

[KarTek]

Where do you guys get a tach signal for the dyno? Do you have to use the optical sensor or is there a wire coming off the tach amp. you can use?

I'd like to find a signal wire on my 606 but I may have to settle for having them tape the damper and fit the optical sensor.

Optical sensor is the best. Any reputable dyno operator will have that accessory.