Good question. I haven't been able to find anything in Motorola's scant online documentation for this or in their press-releases stating what the 1394 connections on these STBs are for--the spec-sheet
just says that they're optional. CableLab's OpenCable Bi-Directional Set-Top Terminal spec
requires HD video pass-thru over 1394, but Motorola doesn't claim that this thing is OpenCable compliant.
Only someone with both an HD D-VHS VCR and HD cable service using this box could say for sure.
-- Mike Scott