I was not aware of the earlier 158 and 208 racks until a 208 full of 411 NR modules presented itself to me the other day. I see in the 900 rack manual that the 410 and 411 modules are listed as OK to work in a 900 rack, but find the 900 series modules I have won't fit in the 208 rack because of a series of notches in the 208 metalwork which guide the circuit board in. If the backplane connections and PSU are otherwise the same, one could add additional notches to a 208 rack for 900 modules. I can't find any real info on the 208 or 158 racks out there, seems like something we need to find for the tech documents section. There is a bit of a 410/411 service manual on the DBX site, but that's it. Anyone know, or have anything?