Hello, You should be using the digi port, and there is a specific setting that allows you to center the filter passband around typical digi signals. I find 200 hz up works best for ALE.
Since the signal is now centered, I can then even use the DSP bandpass to really tighten up. If you have not centered the signal, or are using USB you will need to turn DSP bandpass off. I don't know how the signalink interfaces, but the 857/897 needs no interface for soundcard/tnc usage and is already decoupled at the digi-port on the back of the radio. Have fun, Alan km4ba