As with the Icon 600, is there a document showing the touch phone/mic pod limitations for these systems, as I believe it's different to the 600?
I've just tested an Icon 400 > Touch Phone > Mic Pod and it works, but don't have another Mic Pod to daisy chain, as we have a customer who says this is failing?
Tethered (to the Phone) Mic Pods are not supported at all on the 400 family and withh typically result in an error message when connected. There is an idea here to add support:
Support for additional Digital MicPods on Icon 400/450