Note that all E949 discriminators were in Update mode in the fall of 2001. (The simple explanation of update is that the output width is fixed, unless your pulse goes below threshold and then back above threshold while the output is still high - then you get another fixed width.) We have been discussing the use of Burst Guard. (The simple explanation is that Burst Guard is "time-over-threshold".)
We use mainly the LRS4413 , on the RS, BV, BVL, TT. We use the faster LRS3412 on Ck and Cpi. We use CFD's on the EC LRS3420.