EW to Garmin 196 interface problem

Does anyone use a EW model B data recorder(upgraded
to accept GPS nema) connected to a Garmin 196 for
flight verication? I have a problem with the combo.
I was using a Garmin 90 connected to a SN10 and the
EW without problems. The interface for the 90 was set
to Nema/Nema 2.0. I replaced
the 90 with a 196 and now when I am connected to both
the EW and the SN10 I get a GPSD and then a GPSC, a
disconnect then reconnect, every time the EW requests
a sample. The SN10's file does not show any problems.
If I connect only the EW to the 196 this does not happen.
I have tried this with a seperate cable and it works
fine. If I connect the 90 back it works fine. I have
played with the advanced settings on the 196 without
good results. According to the manual on the 196 it
can feed 3 or more devices and should not have any
problems. I have emailed Graham at EW but have not
heard back from him yet. Anyone have any ideas?