we had a colocated 5ess with a dms100 and a gtd5. Each had advantages. The 5ess was incompatible with so much customer station equipment, we were always doing workarounds to fix the complaints. -Tech support for that from Lucent was a p.i.t.a. And while the 5ess concentration ratios were like others, the numbers were smaller, i.e. just a few line hogs could kill dial tone access for many. That was because it really is a one stage analog switch (diode gates) connecting lines to a digital network. Newer versions changed that dumb design.
